Remove unnecessary ceilometer service overrides

The ceilometer services were removed from core devstack a long ago[1].
Unless the additional plugins are installed, overriding status of
the ceilometer services is just useless.

[1] e9a4750fe1b111eeb457378c26ca9eea1b5e0085

Change-Id: I236f809f7866d719acee8231536d2c26d2456447

zuul.d/base.yaml

@@ -110,13 +110,6 @@
               not_implemented_is_error: False
       devstack_services:
         c-bak: false
-        ceilometer-acentral: false
-        ceilometer-acompute: false
-        ceilometer-alarm-evaluator: false
-        ceilometer-alarm-notifier: false
-        ceilometer-anotification: false
-        ceilometer-api: false
-        ceilometer-collector: false
         c-sch: false
         c-api: false
         c-vol: false