* _ReadLock() will now fail with B_NO_MEMORY in case the ReadLockInfo couldn't
be created.
* Note, due to a design bug, we cannot guarantee that a previous read lock
can be reestablished after releasing a write lock in case of low memory.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17332 a95241bf-73f2-0310-859d-f6bbb57e9c96