git-gui: Fix switch statement in lib/merge.tcl

From: Johannes Sixt <[email protected]>

0aea2842 (Make Ctrl-T safe to use for conflicting files) introduced a new case, but forgot the '-' to indicate that it shares the body with the subsequent case label.

---
 lib/merge.tcl |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index ac4c7de..283e491 100644
@@ -40,7 +40,7 @@ The rescan will be automatically started now.
 		_O {
 			continue; # and pray it works!
 		}
-		_U
+		_U -
 		U? {
 			error_popup [mc "You are in the middle of a conflicted merge.
 

1.6.0.2.1596.g729fb