bitbake: toaster: improve the buildenvironment API

We improve the buildenvironment API by reducing it to a single
command: triggerBuild.

This command is specifically implemented in each BE controller
type, so the runbuilds management command is only concerned
with scheduling the next build, and not with the details
of how a build is actually started.

(Bitbake rev: 7ee0f1da0a8fcac37419ffdddbe35a9268a1ded4)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/bldcontrol/bbcontroller.py

@@ -190,6 +190,9 @@ class BuildEnvironmentController(object):
         """
         raise Exception("Must override BE release")
 
+    def triggerBuild(self, bitbake, layers, variables, targets):
+        raise Exception("Must override BE release")
+
 class ShellCmdException(Exception):
     pass