Fix minor issues

* Remove BIND_PRIV handling since there is no need for it according to jacobalberty#362
* Add functionality to ensure that system.properties file is always created, even if no settings are actally written
* Backport permset handling from master

docker-entrypoint.sh

@@ -161,7 +161,7 @@ fi
 
 UNIFI_CMD="java ${JVM_OPTS} -jar ${BASEDIR}/lib/ace.jar start"
 
-if  command -v permset &> /dev/null
+if [ "$EUID" -ne 0 ] &&  command -v permset &> /dev/null
 then
   permset
 fi
@@ -182,6 +182,9 @@ if [[ "${@}" == "unifi" ]]; then
             mkdir -p "${dir}"
         fi
     done
+    if [[ "$newfile" == "true" ]]; then
+        touch "$confFile"
+    fi
     for key in "${!settings[@]}"; do
       confSet "$confFile" "$key" "${settings[$key]}"
     done
@@ -191,16 +194,6 @@ if [[ "${@}" == "unifi" ]]; then
         fi
         ${UNIFI_CMD} &
     elif [ "${RUNAS_UID0}" == "false" ]; then
-        if [ "${BIND_PRIV}" == "true" ]; then
-            if setcap 'cap_net_bind_service=+ep' "${JAVA_HOME}/jre/bin/java"; then
-                sleep 1
-            else
-                log "ERROR: setcap failed, can not continue"
-                log "ERROR: You may either launch with -e BIND_PRIV=false and only use ports >1024"
-                log "ERROR: or run this container as root with -e RUNAS_UID0=true"
-                exit 1
-            fi
-        fi
         if [ "$(id unifi -u)" != "${UNIFI_UID}" ] || [ "$(id unifi -g)" != "${UNIFI_GID}" ]; then
             log "INFO: Changing 'unifi' UID to '${UNIFI_UID}' and GID to '${UNIFI_GID}'"
             usermod -o -u ${UNIFI_UID} unifi && groupmod -o -g ${UNIFI_GID} unifi