(mc_search__run_regex): minor optimization.

Since mc_search__run_regex() pften is called in various iterative
procedures, don't reallocate regex buffer every time and use already
allocated one before.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

lib/search/regex.c

@@ -878,9 +878,9 @@ mc_search__run_regex (mc_search_t * lc_mc_search, const void *user_data,
     gint end_pos;
 
     if (lc_mc_search->regex_buffer != NULL)
-        g_string_free (lc_mc_search->regex_buffer, TRUE);
-
-    lc_mc_search->regex_buffer = g_string_sized_new (64);
+        g_string_set_size (lc_mc_search->regex_buffer, 0);
+    else
+        lc_mc_search->regex_buffer = g_string_sized_new (64);
 
     virtual_pos = current_pos = start_search;
     while (virtual_pos <= end_search)