Wrap commit instead of calling pretxncommit hook
a) probably faster
b) relying on pretxncommit hook is problematic [issue273]
This version "openly" updates dirstate after overwriting files
after commit.
Changed test output accordingly.
536c1797202d57efb77bea098e10968ff01602ce universal_scheme
ba000e29ecf3b8df09e0fd363a78cabbe3c2a78f cvs_scheme
1fe48bf82d056f1ece05baccab888357c10c5ab8 r0.1
2e930f84224222ad6514a3c5dc6e00350e199e92 very_cvs
99dc49c5bcfba9d5b412c5fa6d0bf3ba20d68df1 hgkw_standalone_setup