Add remove external lock files API in lockutils

when external lock are used, there will be a lock files which
is used for external file lock, it will not be removed and remain
forever. it will be a problem when tens of thousands of this kind
of actions. Add a API to allow other component to remove lock file
internal lock will be acquired before further action

Change-Id: I4d996b91bcc55becb0ebf4ec77ac80546f433ae9
Closes-Bug: 1256306
Merge "Add remove external lock files API in lockutils"