Fixes problems with database - swss - syncd synchronization. (#110)

* [syncd.service] Make syncd starting after swss in order to eliminate race condition with database flush/set

* [swss.service] Make swss waiting for redis server start before cleaning the database

* Fixed review comments for changes in swss service file

Author: Vitaliy Senchyshyn

ansible/roles/sonicv2/templates/etc/systemd/system/swss.j2

@@ -5,6 +5,8 @@ After=database.service
 
 [Service]
 User={{ sonicadmin_user }}
+# Wait for redis server start before database clean
+ExecStartPre=/bin/bash -c "while true; do if [ \"$(/usr/bin/docker exec database redis-cli ping)\" == \"PONG\" ]; then break; fi; sleep 1; done"
 ExecStartPre=/usr/bin/docker exec database redis-cli -n 0 FLUSHDB
 ExecStartPre=/usr/bin/docker exec database redis-cli -n 1 FLUSHDB
 ExecStartPre=/usr/bin/docker exec database redis-cli -n 2 FLUSHDB

ansible/roles/sonicv2/templates/etc/systemd/system/syncd.j2

@@ -1,7 +1,7 @@
 [Unit]
 Description=syncd container
-Requires=database.service
-After=database.service
+Requires=database.service swss.service
+After=database.service swss.service
 
 [Service]
 User=root