jenkins: gerrit-builds: replace the label linux_amd64_debian8/9 -> osmocom-gerrit-debian8/9

Introduce more precise labels to allow more flexibility when extending the jenkins setup.
The linux_amd64_debian8 or linux_amd64_debian9 is used across all build jobs which
make it hard to add new nodes which might only support one group of
jobs.

Change-Id: I900b7b50b33cc95e127ca78d2a47f59d32a6dfee

jobs/README.adoc

@@ -102,3 +102,5 @@ Please use the following labels
 
 - osmocom-master-debian8: are nodes which can build osmocom-master and is a debian 8
 - osmocom-master-debian9: are nodes which can build osmocom-master and is a debian 9
+- osmocom-gerrit-debian8: are nodes which can build osmocom-gerrit and is a debian 8
+- osmocom-gerrit-debian9: are nodes which can build osmocom-gerrit and is a debian 9

jobs/gerrit-verifications.yml

@@ -6,9 +6,9 @@
     # following default values can be overridden by each repo
     disabled: false
     concurrent: false
-    node: linux_amd64_debian8
+    node: osmocom-gerrit-debian8
     # axes related defaults
-    slave_axis: !!python/tuple [linux_amd64_debian8]
+    slave_axis: !!python/tuple [osmocom-gerrit-debian8]
     a1_name: a1
     a1: !!python/tuple [default]
     a2_name: a2
@@ -109,7 +109,7 @@
       - osmo-gsm-manuals
 
       - osmo-hlr:
-          slave_axis: !!python/tuple [linux_amd64_debian8, linux_amd64_debian9]
+          slave_axis: !!python/tuple [osmocom-gerrit-debian8, osmocom-gerrit-debian9]
 
       - osmo-iuh
 
@@ -174,7 +174,7 @@
       - osmo-sip-connector
 
       - osmo-trx:
-          slave_axis: !!python/tuple [linux_amd64_debian9]
+          slave_axis: !!python/tuple [osmocom-gerrit-debian9]
           a1_name: INSTR
           a1: !!python/tuple [--with-sse, --with-neon, --with-neon-vfpv4]
           concurrent: true