Polish next_free_port

Change-Id: Ia8e168790894e16b60639a9cbfc587e7f3d97466

omd/packages/omd/next_free_port

@@ -6,40 +6,40 @@
 
 
 port_is_used () {
-    local KEY=$1
-    local PORT=$2
+    local KEY="${1}"
+    local PORT="${2}"
     for S in $(ls /omd/sites); do
-        if [ ! -d /omd/sites/$S ]; then
+        if [ ! -d /omd/sites/"${S}" ]; then
             continue
         fi
 
-        site_conf=/omd/sites/$S/etc/omd/site.conf
+        site_conf="/omd/sites/${S}/etc/omd/site.conf"
 
         if [ "${S}" = "${OMD_SITE}" ]; then
             # happens when a new site is created
             if [ ! -f "${site_conf}" ]; then
                 continue
             fi
-            if [ $(grep "='${PORT}'" "$site_conf" | grep -v "${KEY}" | wc -l) -gt 0 ]; then
+            if [ $(grep "='${PORT}'" "${site_conf}" | grep -v "${KEY}" | wc -l) -gt 0 ]; then
                 return 0
             fi
         else
-            if ! ls $site_conf >/dev/null 2>&1; then
+            if ! ls "${site_conf}" >/dev/null 2>&1; then
                 echo "ERROR: Failed to read config ${conf} of site ${S}. ${KEY} port will possibly be allocated twice" >&2
                 continue
             fi
 
-            if [ $(grep -v ^#  < $site_conf | grep "='${PORT}'" | wc -l) -gt 0 ]; then
+            if [ $(grep -v ^#  < "${site_conf}" | grep "='${PORT}'" | wc -l) -gt 0 ]; then
                 return 0
             fi
         fi
     done
     return 1
 }
 
-KEY=$1
-PORT=$2
-while port_is_used "$KEY" "$PORT"; do
+KEY="${1}"
+PORT="${2}"
+while port_is_used "${KEY}" "${PORT}"; do
     PORT=$((PORT + 1))
 done
-echo "$PORT"
+echo "${PORT}"