Check idl.run() return value before blocking
Check idl.run() return value before blocking

The IDL change_seqno can change as a result of running idl.run(), and
it returns True if there has been a change. The existing code would
block without checking the return value, and therefor could block
until another change occurred, or the timeout was reached.

Closes-Bug: #1501090
Change-Id: I9b7aac2755e6e6b69165023e01583337f9d30f15

yanheven/neutron,noironetworks/neutron,jumpojoy/neutron,openstack/neutron,igor-toga/local-snat,eayunstack/neutron,apporc/neutron,wolverineav/neutron,glove747/liberty-neutron,wolverineav/neutron,dims/neutron,cloudbase/neutron,MaximNevrov/neutron,dhanunjaya/neutron,sebrandon1/neutron,mahak/neutron,jumpojoy/neutron,openstack/neutron,yanheven/neutron,asgard-lab/neutron,bigswitch/neutron,cloudbase/neutron,asgard-lab/neutron,dhanunjaya/neutron,chitr/neutron,klmitch/neutron,mahak/neutron,bigswitch/neutron,dims/neutron,noironetworks/neutron,klmitch/neutron,mahak/neutron,igor-toga/local-snat,glove747/liberty-neutron,eayunstack/neutron,apporc/neutron,openstack/neutron,huntxu/neutron,sebrandon1/neutron,chitr/neutron,huntxu/neutron,MaximNevrov/neutron