set host=xos_db; resolves synchronizer no-start issue

Change-Id: I414511800685976f8722804332ab0bc255d99b63
(cherry picked from commit febcfe6133d40361d94916d7c74e1ee8d735c074)
diff --git a/xos/synchronizer/vpgwc_config b/xos/synchronizer/vpgwc_config
index d5cf77c..7e00dd8 100755
--- a/xos/synchronizer/vpgwc_config
+++ b/xos/synchronizer/vpgwc_config
@@ -3,7 +3,7 @@
 name=xos
 user=postgres
 password=password
-host=localhost
+host=xos_db
 port=5432
 
 # Required by XOS