bitbake: toaster: notify runbuilds when build status changes

Called signal_runbuilds API when build is scheduled, cancelled or
finished to notify runbuilds process about builds status change.

[YOCTO #8918]

(Bitbake rev: fe08f0fa4b328908e73695ebbceca87bc86a49f9)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Michael Wood <michael.g.wood@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/orm/models.py

@@ -377,6 +377,8 @@ class Project(models.Model):
             except ProjectVariable.DoesNotExist:
                 pass
             br.save()
+            signal_runbuilds()
+
         except Exception:
             # revert the build request creation since we're not done cleanly
             br.delete()