w32: Fix another memleak on error.

* src/w32-io.c (create_reader): free CTX.
--

Found by Hans-Christoph Steiner with cppcheck.

src/engine-gpg.c

@@ -896,6 +896,10 @@ build_argv (engine_gpg_t gpg)
 					       close_notify_handler,
 					       gpg))
 	      {
+                /* We leak fd_data_map and the fds.  This is not easy
+                   to avoid and given that we reach this here only
+                   after a malloc failure for a small object, it is
+                   probably better not to do anything.  */
 		return gpg_error (GPG_ERR_GENERAL);
 	      }
 	    /* If the data_type is FD, we have to do a dup2 here.  */

src/w32-io.c

@@ -425,6 +425,7 @@ create_reader (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",