Fix a memory leak in rsakey_pubblob

The line read from the input file was not freed after successfully
loading an SSH1 key.

sshpubk.c

@@ -309,6 +309,7 @@ int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
             *commentptr = commentp ? dupstr(commentp) : NULL;
         *blob = rsa_public_blob(&key, bloblen);
         freersakey(&key);
+        sfree(line);
         fclose(fp);
         return 1;