schedulers: Clean up build-appliance srcrev code

We need to show the build-appliance configuration on nightly as well as
nightly-build-appliance.

Also, default to AUTOREV, matching the behaviour of the old codebase.

Drop the "DEFAULT" magic value, default to that if a revision isn't specified.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

TODO

@@ -3,7 +3,6 @@
  * Add wikilog link on console page
  * implement buildhistory writeback step in -helper (can then drop from builders.py) [Richard]
  * per worker auth (workers.py & config.py)
- * DEFAULT for buildapp SRCREV still true? (schedulers.py)
  * Add IRC notifier (services.py) [Michael]
  * formatting/labels of the yocto-autobuilder-helper inputs (schedulers.py) [Paul]
  * add mail notification functionality to yocto-autobuilder-helper, it already

schedulers.py

@@ -43,6 +43,11 @@ def repos_for_builder(buildername):
         parameters = parameters + inputs
     return parameters
 
+def buildappsrcrev_param():
+    return util.StringParameter(
+            name="buildappsrcrev",
+            label="""Build appliance source revision to use. Empty defaults to the srcrev currently in the recipe, use AUTOREV to use latest revision:""",
+            default="AUTOREV")
 
 def props_for_builder(builder):
     """
@@ -52,13 +57,7 @@ def props_for_builder(builder):
 
     props = []
     if builder == 'build-appliance':
-        props.append(util.StringParameter(
-            name="buildappsrcrev",
-            # TODO: is this statement still true?
-            label="""Build appliance src revision. Use DEFAULT to take the
- srcrev currently in the recipe:""",
-            default="None",
-        ))
+        props.append(buildappsrcrev_param())
     if builder in ['build-appliance', 'buildtools']:
         props.append(util.BooleanParameter(
             name="deploy_artifacts",
@@ -98,6 +97,7 @@ schedulers.append(sched.ForceScheduler(
  any expectations for the build's outcome:""",
         required=False),
     properties=[
+        buildappsrcrev_param(),
         util.BooleanParameter(
             name="is_release",
             label="Generate a release?",