TT#20091 Simplify influxdb list check (no need to grep output, goss has builtin functions)

Change-Id: Ib86e1b7e9b9bca3d1fdb0e395434744732742188

templates/910_service-influxdb.yaml.tt2

@@ -1,23 +1,12 @@
 command:
 
-  influx -execute 'show databases' | grep _internal:
+  influx -execute 'show databases':
     exit-status: 0
     stdout:
-    - _internal
-    stderr: []
-    timeout: 10000
-
-  influx -execute 'show databases' | grep ngcp:
-    exit-status: 0
-    stdout:
-    - ngcp
-    stderr: []
-    timeout: 10000
-
-  influx -execute 'show databases' | grep telegraf:
-    exit-status: 0
-    stdout:
-    - telegraf
+    - "/^name: databases$/"
+    - "/^_internal$/"
+    - "/^ngcp$/"
+    - "/^telegraf$/"
     stderr: []
     timeout: 10000