w32: Fix memleak in an error code paths.

* src/w32-io.c (create_writer): Free CTX in cased of bad FD.
* src/w32-util.c (_gpgme_mkstemp): Free TMPNAME in case of a failed
mkstemp.
--

Found by Hans-Christoph Steiner with cppcheck.

src/w32-io.c

@@ -794,6 +794,7 @@ create_writer (int fd)
   if (fd < 0 || fd >= MAX_SLAFD || !fd_table[fd].used)
     {
       TRACE_SYSERR (EIO);
+      free (ctx);
       return NULL;
     }
   TRACE_LOG4 ("fd=%d -> handle=%p socket=%d dupfrom=%d",

src/w32-util.c

@@ -660,7 +660,10 @@ _gpgme_mkstemp (int *fd, char **name)
   strcpy (stpcpy (tmpname, tmp), "\\gpgme-XXXXXX");
   *fd = mkstemp (tmpname);
   if (fd < 0)
-    return -1;
+    {
+      free (tmpname);
+      return -1;
+    }
 
   *name = tmpname;
   return 0;