TT#177550 check: Add code to check the multi-site setup

This off-loads the check to the ngcp-site script, and prints any error
message from it if the script fails.

Only run the check if ngcp-site is present, so that we avoid a
hard-dependency on system-tools.

Change-Id: I640f85383d424980d81a207dee7d586a88422862

scripts/check

@@ -90,6 +90,20 @@ check_origin() {
   fi
 }
 
+check_multi_site() {
+  log_debug "Checking multi-site support"
+  if ! command -v ngcp-site >/dev/null; then
+    log_debug "Skipping check due to missing ngcp-site"
+    return 0
+  fi
+
+  if ! error=$(ngcp-site 2>&1 >/dev/null); then
+    log_error "Configuration problem with multi-site setup."
+    log_error "${error}"
+    exit 1
+  fi
+}
+
 check_config_encoding() {
   log_debug "Checking encoding for $config_files"
   for f in $config_files ; do
@@ -245,6 +259,8 @@ check_branch
 
 check_origin
 
+check_multi_site
+
 check_configs
 if "${VALIDATE_SCHEMA:-false}" || [ "${VALIDATE:-0}" = "1" ] ; then
   validate_config