implement EGW_SKIP_INSTALL for entrypoint to skip automatic install

also fixed not working exit on failed install

doc/docker/fpm/entrypoint.sh

@@ -1,6 +1,5 @@
 #!/bin/bash
 set -e
-set -x
 
 # ToDo check version before copy
 rsync -a --delete /usr/share/egroupware-sources/ /usr/share/egroupware/
@@ -19,8 +18,10 @@ touch $LOG
 chmod 600 $LOG
 
 max_retries=10
-try=0
-until php /usr/share/egroupware/doc/rpm-build/post_install.php \
+export try=0
+# EGW_SKIP_INSTALL=true skips initial installation (no header.inc.php yet)
+until [ -n "$EGW_SKIP_INSTALL" -a ! -f /var/lib/egroupware/header.inc.php ] || \
+	php /usr/share/egroupware/doc/rpm-build/post_install.php \
 	--start_webserver "" --autostart_webserver "" \
 	--start_db "" --autostart_db "" \
 	--db_type "${EGW_DB_TYPE:-mysqli}" \
@@ -30,17 +31,19 @@ until php /usr/share/egroupware/doc/rpm-build/post_install.php \
 	--db_root_pw   "${EGW_DB_ROOT_PW:-}" \
 	--db_name "${EGW_DB_NAME:-egroupware}" \
 	--db_user "${EGW_DB_USER:-egroupware}" \
-	--db_pass "${EGW_DB_PASS:-}" || [ "$try" -gt "$max_retries" ]
+	--db_pass "${EGW_DB_PASS:-}"
 do
+	if [ "$try" -gt "$max_retries" ]; then
+		echo "Installing of EGroupware failed!"
+		break
+	fi
 	echo "Retrying EGroupware installation in 3 seconds ..."
 	try=$((try+1))
 	sleep 3s
 done 2>&1 | tee -a $LOG
 
-if [ "$try" -gt "$max_retries" ]; then
-	echo "Installing of EGroupware failed!" | tee -a $LOG
-	exit 1
-fi
+# as we can NOT exit from until (runs a subshell), we need to check and do it here
+[ "$(tail -1 $LOG)" = "Installing of EGroupware failed!" ] && exit 1
 
 # to run async jobs
 service cron start