Remove some redundant variables and assignments.

This fixes a batch of clang-analyzer warnings of the form 'you
declared / assigned this variable and then never use it'. It doesn't
fix _all_ of them - some are there so that when I add code in the
future _it_ can use the variable without me having to remember to
start setting it - but these are the ones I thought it would make the
code better instead of worse to fix.

unix/gtkcols.c

@@ -735,13 +735,10 @@ static void columns_alloc_horiz(Columns *cols, gint ourwidth,
     ColumnsChild *child;
     GList *children;
     gint i, ncols, colspan, border, *colxpos, childwidth;
-    const gint *percentages;
-    static const gint onecol[] = { 100 };
 
     border = gtk_container_get_border_width(GTK_CONTAINER(cols));
 
     ncols = 1;
-    percentages = onecol;
     /* colxpos gives the starting x position of each column.
      * We supply n+1 of them, so that we can find the RH edge easily.
      * All ending x positions are expected to be adjusted afterwards by
@@ -759,12 +756,11 @@ static void columns_alloc_horiz(Columns *cols, gint ourwidth,
 
 	    /* Column reconfiguration. */
 	    ncols = child->ncols;
-	    percentages = child->percentages;
 	    colxpos = g_renew(gint, colxpos, ncols + 1);
 	    colxpos[0] = 0;
 	    percent = 0;
 	    for (i = 0; i < ncols; i++) {
-		percent += percentages[i];
+		percent += child->percentages[i];
 		colxpos[i+1] = (((ourwidth - 2*border) + cols->spacing)
 				* percent / 100);
 	    }

unix/uxnet.c

@@ -794,7 +794,6 @@ Socket *sk_new(SockAddr *addr, int port, bool privport, bool oobinline,
     ret->privport = privport;
     ret->port = port;
 
-    err = 0;
     do {
         err = try_connect(ret);
     } while (err && sk_nextaddr(ret->addr, &ret->step));

unix/uxpgnt.c

@@ -734,14 +734,14 @@ void run_agent(void)
     unsigned long now;
     int *fdlist;
     int fd;
-    int i, fdcount, fdsize, fdstate;
+    int i, fdsize, fdstate;
     int termination_pid = -1;
     bool errors = false;
     Conf *conf;
     const struct cmdline_key_action *act;
 
     fdlist = NULL;
-    fdcount = fdsize = 0;
+    fdsize = 0;
 
     pageant_init();
 
@@ -891,7 +891,7 @@ void run_agent(void)
 	 * Add all currently open fds to the select sets, and store
 	 * them in fdlist as well.
 	 */
-	fdcount = 0;
+	int fdcount = 0;
 	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
 	     fd = next_fd(&fdstate, &rwx)) {
 	    fdlist[fdcount++] = fd;

unix/uxplink.c

@@ -561,7 +561,7 @@ int main(int argc, char **argv)
     bool sending;
     int *fdlist;
     int fd;
-    int i, fdcount, fdsize, fdstate;
+    int i, fdsize, fdstate;
     int exitcode;
     bool errors;
     bool use_subsystem = false;
@@ -571,7 +571,7 @@ int main(int argc, char **argv)
     const struct BackendVtable *backvt;
 
     fdlist = NULL;
-    fdcount = fdsize = 0;
+    fdsize = 0;
     /*
      * Initialise port and protocol to sensible defaults. (These
      * will be overridden by more or less anything.)
@@ -878,7 +878,7 @@ int main(int argc, char **argv)
 	 * Add all currently open fds to the select sets, and store
 	 * them in fdlist as well.
 	 */
-	fdcount = 0;
+	int fdcount = 0;
 	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
 	     fd = next_fd(&fdstate, &rwx)) {
 	    fdlist[fdcount++] = fd;

unix/uxserver.c

@@ -359,7 +359,7 @@ int main(int argc, char **argv)
 {
     int *fdlist;
     int fd;
-    int i, fdcount, fdsize, fdstate;
+    int i, fdsize, fdstate;
     unsigned long now;
 
     ssh_key **hostkeys = NULL;
@@ -531,7 +531,7 @@ int main(int argc, char **argv)
     }
 
     fdlist = NULL;
-    fdcount = fdsize = 0;
+    fdsize = 0;
 
     random_ref();
 
@@ -580,7 +580,7 @@ int main(int argc, char **argv)
 	 * Add all currently open fds to the select sets, and store
 	 * them in fdlist as well.
 	 */
-	fdcount = 0;
+	int fdcount = 0;
 	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
 	     fd = next_fd(&fdstate, &rwx)) {
 	    fdlist[fdcount++] = fd;

unix/uxsftp.c

@@ -445,14 +445,14 @@ char *dir_file_cat(const char *dir, const char *file)
 static int ssh_sftp_do_select(bool include_stdin, bool no_fds_ok)
 {
     fd_set rset, wset, xset;
-    int i, fdcount, fdsize, *fdlist;
-    int fd, fdstate, rwx, ret, maxfd;
+    int i, fdsize, *fdlist;
+    int fd, fdcount, fdstate, rwx, ret, maxfd;
     unsigned long now = GETTICKCOUNT();
     unsigned long next;
     bool done_something = false;
 
     fdlist = NULL;
-    fdcount = fdsize = 0;
+    fdsize = 0;
 
     do {