tests/test-requires.t

splicemap: improve error handling when source is hg (issue2084)

1. Introduced 2 levels of error handling for splicemap files
   a. Check the splicemap file for rules which are same across different
      types of source repos.  This is done through enhancing parsesplicemap
      function
   b. Check revision string formats.  Each repo may have their own format.
      This is done usign checkrevformat function
   c. Implemented the above two for hg

  $ hg init t
  $ cd t
  $ echo a > a
  $ hg add a
  $ hg commit -m test
  $ rm .hg/requires
  $ hg tip
  abort: index 00changelog.i unknown format 2!
  [255]
  $ echo indoor-pool > .hg/requires
  $ hg tip
  abort: unknown repository format: requires features 'indoor-pool' (upgrade Mercurial)!
  [255]
  $ echo outdoor-pool >> .hg/requires
  $ hg tip
  abort: unknown repository format: requires features 'indoor-pool', 'outdoor-pool' (upgrade Mercurial)!
  [255]

  $ cd ..