git-merge: minor fix for no_trivial_merge_strategies.

The shell loop to determine if we should skip the trivial
in-index merge stage based on what strategy is given was not
prepared to have more than one strategy listed in the variable
$no_trivial_merge_strategies.

This does not trigger unless you use a modified git but the fix
is simple and straightforward, so let's fix it before 1.5.0.1.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-merge.sh

@@ -253,14 +253,17 @@ case "$use_strategies" in
 esac
 
 for s in $use_strategies
+do
+	for nt in $no_trivial_merge_strategies
 	do
 		case " $s " in
-	*" $no_trivial_merge_strategies "*)
+		*" $nt "*)
 			index_merge=f
 			break
 			;;
 		esac
 	done
+done
 
 case "$#" in
 1)