bitbake: runbuilds: code cleanup - remove unused imports

Fixed pylint warning:  W0611(unused-import): Unused import

(Bitbake rev: 49731a1a2b2b63c1a897d2e33bca4968524e8710)

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/bldcontrol/management/commands/runbuilds.py

@@ -1,17 +1,14 @@
-from django.core.management.base import NoArgsCommand, CommandError
+from django.core.management.base import NoArgsCommand
 from django.db import transaction
 from django.db.models import Q
 
 from bldcontrol.bbcontroller import getBuildEnvironmentController
-from bldcontrol.bbcontroller import ShellCmdException, BuildSetupException
 from bldcontrol.models import BuildRequest, BuildEnvironment
 from bldcontrol.models import BRError, BRVariable
 
-from orm.models import Build, ToasterSetting, LogMessage, Target
+from orm.models import Build, LogMessage, Target
 
-import os
 import logging
-import sys
 import traceback
 import signal