module/gerrit: track container user in a dedicated variable
diff --git a/module/gerrit/holder.sh b/module/gerrit/holder.sh
index 5774c12..f848f66 100644
--- a/module/gerrit/holder.sh
+++ b/module/gerrit/holder.sh
@@ -67,3 +67,4 @@
 	_GERRIT_APT_GET_INSTALL_NMAP_="# Skip install nmap for ${mod_mode}"
 	_GERRIT_APT_GET_INSTALL_PING_="# Skip install ping for ${mod_mode}"
 fi
+_GERRIT_USER_CON_="root"
diff --git a/module/gerrit/scheme.sh b/module/gerrit/scheme.sh
index f034429..3a066ce 100644
--- a/module/gerrit/scheme.sh
+++ b/module/gerrit/scheme.sh
@@ -93,7 +93,7 @@
 	directory = cache
 
 [container]
-	user = root
+	user = ${_GERRIT_USER_CON_}
 
 [receive]
 	enableSignedPush = false
@@ -139,7 +139,7 @@
 	chown -R gerrit:gerrit /var/gerrit
 
 # Debian 9 fails with 'USER gerrit'
-USER root
+USER ${_GERRIT_USER_CON_}
 
 # Define environment
 ENV CANONICAL_WEB_URL=