small fixes for test-newbranch - hg tip doesn't use the branch cache; use hg log -r in its place - commit doesn't use a HG_MERGE environment variable - change the dates from "0 0" to "1000000 0"

1 files updated, 0 files merged, 0 files removed, 0 files unresolved
removing b
abort: update spans branches, use 'hg merge' or 'hg update -C' to lose changes