coverity-scan.sh: inherity $JEHANNE if defined

coverity-scan.sh

@@ -2,8 +2,10 @@
 set -e
 
 if [ "${COVERITY_SCAN_BRANCH}" != 1 ]; then
+	if [ -z "$JEHANNE" ]; then
 		export JEHANNE=`git rev-parse --show-toplevel|sed 's/\/hacking//g'`
-	export PATH="$JEHANNE/hacking:$PATH"
+		export PATH="$JEHANNE/hacking/bin:$PATH"
+	fi
 	export SH=`which rc`
 	export ARCH=amd64
 	git clean -x -d -f