gerrit.sh: Corrected typo in error message

Change-Id: I8a6ec4ff6d5ae7b502636742737df3a67615cbdb
diff --git a/gerrit-pgm/src/main/resources/com/google/gerrit/pgm/gerrit.sh b/gerrit-pgm/src/main/resources/com/google/gerrit/pgm/gerrit.sh
index 4148847..51b7d1a 100755
--- a/gerrit-pgm/src/main/resources/com/google/gerrit/pgm/gerrit.sh
+++ b/gerrit-pgm/src/main/resources/com/google/gerrit/pgm/gerrit.sh
@@ -302,7 +302,7 @@
   done
 fi
 if test -z "$GERRIT_WAR" ; then
-  echo >&2 "** ERROR: Cannot find gerrit.war (try setting gerrit.war)"
+  echo >&2 "** ERROR: Cannot find gerrit.war (try setting \$GERRIT_WAR)"
   exit 1
 fi