Fix segv for userids with a backslash.

* src/engine-gpg.c (gpg_keylist_preprocess): Increment SRC for a
backslash.
--

This bug is not exploitable because this bug fills up .data with
backslashes and thus causes the segv.

Signed-off-by: Werner Koch <wk@gnupg.org>

src/engine-gpg.c

@@ -2194,6 +2194,7 @@ gpg_keylist_preprocess (char *line, char **r_line)
               {
                 *dst++ = '\\';
                 *dst++ = '\\';
+                src++;
               }
 	    else
 	      *(dst++) = *(src++);