gerrit.sh: Avoid 'test ==' for portability

'test ==' is a more modern version of 'test =', but it is not supported
on ubuntu 22.04.5, avoid it for better portability.

Release-Notes: skip
Change-Id: Ie753d2d7f9625855d72f0f40e6b0d085a3cb648c
diff --git a/resources/com/google/gerrit/pgm/init/gerrit.sh b/resources/com/google/gerrit/pgm/init/gerrit.sh
index dc56fae..4dc8881 100755
--- a/resources/com/google/gerrit/pgm/init/gerrit.sh
+++ b/resources/com/google/gerrit/pgm/init/gerrit.sh
@@ -371,7 +371,7 @@
 
 GERRIT_USER=`get_config --get container.user`
 
-if test "$(uname -s)" == "Darwin" ; then
+if test "$(uname -s)" = "Darwin" ; then
   JAVA_OPTIONS="$JAVA_OPTIONS -XX:-MaxFDLimit"
 fi