Correct key bindings to Control-<foo>

Alberto Bertogli reported on #git that git-gui was exiting with
alt-q, while gitk on the same system was exiting with ctrl-q.
That was not what I wanted.  I really wanted M1B to be bound to
the Control key on most non-Mac OS X platforms, but according to
Sam Vilain M1 on most systems means alt.  Since gitk always does
control, I'm doing the same thing for all non-Mac OS X systems.

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

git-gui.sh

@@ -1206,15 +1206,12 @@ foreach class {Button Checkbutton Entry Label
 }
 unset class
 
-if {[is_Windows]} {
-	set M1B Control
-	set M1T Ctrl
-} elseif {[is_MacOSX]} {
+if {[is_MacOSX]} {
 	set M1B M1
 	set M1T Cmd
 } else {
-	set M1B M1
-	set M1T M1
+	set M1B Control
+	set M1T Ctrl
 }
 
 proc apply_config {} {