git-gui: Attempt to checkout the new branch after creation.

If the user asked us to checkout the branch after creating it then
we should try to do so.  This may fail, especially right now since
branch switching from within git-gui is not supported.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

git-gui.sh

@@ -1674,6 +1674,9 @@ proc do_create_branch_action {w} {
 	set all_heads [lsort $all_heads]
 	populate_branch_menu
 	destroy $w
+	if {$create_branch_checkout} {
+		switch_branch $newbranch
+	}
 }
 
 proc do_create_branch {} {
@@ -1681,7 +1684,7 @@ proc do_create_branch {} {
 	global create_branch_checkout create_branch_revtype
 	global create_branch_head create_branch_trackinghead
 
-	set create_branch_checkout true
+	set create_branch_checkout 1
 	set create_branch_revtype head
 	set create_branch_head $current_branch
 	set create_branch_trackinghead {}
@@ -1792,8 +1795,6 @@ proc do_create_branch {} {
 		-font font_ui
 	checkbutton $w.postActions.checkout \
 		-text {Checkout after creation} \
-		-offvalue false \
-		-onvalue true \
 		-variable create_branch_checkout \
 		-font font_ui
 	pack $w.postActions.checkout -anchor nw