Fix CID 715143: assert that the preference we were looking for was found. It

should be which is why this is an assertion not a NULL check.

svn path=/trunk/; revision=52847

epan/prefs.c

@@ -1538,6 +1538,7 @@ static void column_format_reset_cb(pref_t* pref)
     }
 
     col_num_pref = prefs_find_preference(gui_column_module, PRS_COL_NUM);
+    g_assert(col_num_pref != NULL); /* Should never happen */
     column_num_reset_cb(col_num_pref);
 }