del transaction before lock before wlock
This way rollbacks happen while the repo is still locked.
Deleting lock before wlock is not strictly necessary, but is
more consistent with the locking order.
% basic
% unknown
*** [alias] unknown: command bargle is unknown
% ambiguous
*** [alias] ambiguous: command s is ambiguous
% recursive
*** [alias] recursive: circular dependency on recursive
adding foo
% with opts
C foo