Fix bashism.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@185646 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/testit b/test/testit
index a742364..18b0814 100755
--- a/test/testit
+++ b/test/testit
@@ -12,7 +12,7 @@
 origpath=$currentpath
 currentdir=`basename $currentpath`
 while [ $currentdir != "test" ]; do
-	if [ $currentdir == "/" ]
+	if [ $currentdir = "/" ]
 	then
 		echo "current directory must be in or under \"test\"."
 		exit 1