Make shellcheck happy

Author: flexiondotorg

deb-get

@@ -2426,8 +2426,8 @@ if [ -e /etc/os-release ]; then
 #Debian VERSION_CODENAME=$(grep VERSION_CODENAME /etc/os-release | cut -d'=' -f2 | sed 's/"//g')
     UPSTREAM_ID="$(grep "^ID=" /etc/os-release | cut -d'=' -f2)"
     UPSTREAM_ID_LIKE="$(grep "^ID_LIKE=" /etc/os-release | cut -d'=' -f2 | sed s/\"//g | cut -d' ' -f1)"
-    if [ ! -z "$UPSTREAM_ID_LIKE" ]; then
-        UPSTREAM_ID=$UPSTREAM_ID_LIKE
+    if [ ! -z "${UPSTREAM_ID_LIKE}" ]; then
+        UPSTREAM_ID="${UPSTREAM_ID_LIKE}"
     fi
     case "${UPSTREAM_ID}" in
         debian) UPSTREAM_CODENAME=$(grep VERSION_CODENAME /etc/os-release | cut -d'=' -f2);;