- Disentangle the usage of ObpAcquireDirectoryLockExclusive() when it's
used only for accessing a directory structure, or as part of a lookup
operation.
The Obp*DirectoryLock*() -- both shared and exclusive -- functions
are only for locking an OB directory, for reading or writing its
structure members.
When performing lookup operations (insertions/deletions of entries
within a directory), use a ObpAcquireLookupContextLock() function that
exclusively locks the directory and saves extra lock state, that can
be used by ObpReleaseLookupContextObject() for cleanup.
- Add documentation for these functions.