Fix regression in g_shell_parse_argv()

The commit in 6e4acf44b3 broke
the fallthrough case for '\\' when it changed the '#' case.

This caused issues like this:
  https://bugzilla.gnome.org/show_bug.cgi?id=683821

https://bugzilla.gnome.org/show_bug.cgi?id=562907

glib/gshell.c

@@ -518,7 +518,10 @@ tokenize_command_line (const gchar *command_line,
               g_string_append_c (current_token, *p);
 
               /* FALL THRU */
-              
+            case '\\':
+              current_quote = *p;
+              break;
+
             case '#':
               if (p == command_line)
 	        { /* '#' was the first char */
@@ -538,9 +541,6 @@ tokenize_command_line (const gchar *command_line,
 		    break;
                 }
               break;
-            case '\\':
-              current_quote = *p;
-              break;
 
             default:
               /* Combines rules 4) and 6) - if we have a token, append to it,