cfs lock: avoid confusing lock prefix on error

cfs lock: avoid confusing lock prefix on error

we have lots of forum posts where users think that the locking was
the error, not the actual error message from the called code.

This has limited value as general-applied prefix, if a code requires
the lockid or whatever to be included in the error message they can
already do so, so just re-raise the error and be done, at least if it
is a error from the code and not from the lock setup,.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>