Don't run the tarball jobs for core projects on tags.

The tarball script isn't expecting a tag.

Change-Id: I374408ea0aa40ef68beffedeabaa0701b014cb7d
Reviewed-on: https://review.openstack.org/12968
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Tested-by: Jenkins

modules/openstack_project/files/zuul/layout.yaml

@@ -216,7 +216,6 @@ projects:
       - cinder-coverage
       - cinder-docs
     publish:
-      - cinder-tarball
       - cinder-docs
 
   - name: openstack/glance
@@ -241,7 +240,6 @@ projects:
       - glance-coverage
       - glance-docs
     publish:
-      - glance-tarball
       - glance-docs
 
   - name: openstack/horizon
@@ -268,7 +266,6 @@ projects:
       - horizon-coverage
       - horizon-docs
     publish:
-      - horizon-tarball
       - horizon-docs
 
   - name: openstack/keystone
@@ -317,7 +314,6 @@ projects:
       - nova-docs
       - nova-upstream-translation-update
     publish:
-      - nova-tarball
       - nova-docs
 
   - name: openstack/openstack-common
@@ -350,7 +346,6 @@ projects:
       - quantum-coverage
       - quantum-docs
     publish:
-      - quantum-tarball
       - quantum-docs
 
   - name: openstack/swift
@@ -375,7 +370,6 @@ projects:
       - swift-coverage
       - swift-docs
     publish:
-      - swift-tarball
       - swift-docs
 
   - name: openstack/python-cinderclient