ansible: name for git package differs on centos7

When trying to ansible test-rackspace-centos7-x64-1 I found that it
can't install git, because that's 1.8, and it has git216 installed.
So, git can't be shared by all centos7 platforms, the name differs, move
into a more specific package list.

PR-URL: #2262

ansible/roles/baselayout/vars/main.yml

@@ -39,11 +39,14 @@ packages: {
     'ccache,git2u,gcc-c++,devtoolset-6,sudo', # even need gcc on centos6 so ccache has symlinks
   ],
 
+  # centos-release-scl is required to enable SCLo but we do it manually in
+  # partials/repo/centos7.yml for arm64
   centos7_arm64: ['git'], # git2u not available for aarch64 (yet)
-  centos7_x64: ['git2u','centos-release-scl',], # centos-release-scl is required to enable SCLo
-                                               # but we do it manually in partials/repo/centos7.yml for arm64
+  centos7_x64: ['git2u,centos-release-scl'],
+  centos7_ppc64: ['git'],
+
   centos7: [
-    'bzip2-devel,openssl-devel,ccache,gcc-c++,devtoolset-6,sudo,git,devtoolset-6-libatomic-devel,zlib-devel,libffi-devel,devtoolset-8,devtoolset-8-libatomic-devel',
+    'bzip2-devel,openssl-devel,ccache,gcc-c++,devtoolset-6,sudo,devtoolset-6-libatomic-devel,zlib-devel,libffi-devel,devtoolset-8,devtoolset-8-libatomic-devel',
   ],
 
   aix: [