the headroom infomation is incomplete

If multiple resources beyond the quotas in 'limit_check' from
nova/quota.py. The headroom information about the resources
beyond the quotas in OverQuota Exception is incomplete.

Change-Id: I790c22e3618a3558dfad64bf46e37e4e49f6385e
Closes-Bug: #1334965
Merge "the headroom infomation is incomplete"