allow patches remote and branch to be set in git config

this commit allows one to configure an explicit patches remote and
patches branch by setting the 'rdopkg.<branch>.patches-remote' and
'rdopkg.<branch>.patches-branch' git configuration options.

Change-Id: I74d58cd70867b29c06fea1ca261e3c4ccc1406f2

Author: larsks

doc/rdopkg.1.adoc

@@ -590,6 +590,15 @@ Use `rdopkg pkgenv` to check detected patches branch.
 You can specify remote patches branch by `-p`/`--patches-branch` action
 parameter for actions that use it, such as `patch` and `new-version`.
 
+You may explicitly set the name of your patches remote and patches
+branch in your git configuration using the
+`rdopkg.<branch>.patches-remote` and `rdopkg.<branch>.patches-branch`
+options.  For example, if you are working on a `dist-git` branch named
+`rhel-7.4` and you want to use `rhel-7-patches` for your patches
+branch, you would run:
+
+    git config rdopkg.rhel-7.4.patches-branch rhel-7-patches
+
 patches base
 ~~~~~~~~~~~~
 

rdopkg/guess.py

@@ -91,7 +91,14 @@ def version_tag_style(version=None):
 
 
 def find_patches_branch(distgit, remote):
-    pb = '%s/%s-patches' % (remote, distgit)
+    cfg_branch = git.config_get('rdopkg.%s.patches-branch' % distgit)
+
+    if cfg_branch:
+        # if there is an explicitly configured patches branch, use it.
+        pb = '%s/%s' % (remote, cfg_branch)
+    else:
+        pb = '%s/%s-patches' % (remote, distgit)
+
     if git.ref_exists('refs/remotes/%s' % pb):
         return pb
     parts = distgit.split('-')[:-1]
@@ -104,17 +111,24 @@ def find_patches_branch(distgit, remote):
 
 
 def patches_branch(distgit, pkg=None, osdist='RDO'):
-    remotes = ['patches']
-    # support legacy remote names
-    if osdist == 'RHOS':
-        remotes.append('rhos')
+    cfg_remote = git.config_get('rdopkg.%s.patches-remote' % distgit)
+
+    if cfg_remote:
+        # if there is an explicitly configured remote, just use it.
+        remotes = [cfg_remote]
     else:
-        remotes.append('redhat-openstack')
-    # support patches branch in the same remote
-    remote_branch = git.remote_of_local_branch(distgit) or ''
-    remote = remote_branch.partition('/')[0]
-    if remote:
-        remotes.append(remote)
+        remotes = ['patches']
+        # support legacy remote names
+        if osdist == 'RHOS':
+            remotes.append('rhos')
+        else:
+            remotes.append('redhat-openstack')
+
+        # support patches branch in the same remote
+        remote_branch = git.remote_of_local_branch(distgit) or ''
+        remote = remote_branch.partition('/')[0]
+        if remote:
+            remotes.append(remote)
 
     for remote in remotes:
         pb = find_patches_branch(distgit, remote)