Some cvs related fixes and enhancements v2

This patch series

    - fixes a small bug in the cvsimport testsuite
    - adds support for packed-refs to cvsserver
    - adds basic support cvs co -c to cvsserver

Changes to v1:

    - do not change output format of req_up (noticed by Johannes Schindelxein)
    - test output of the cvs client instead of raw server output
    - remove superfluous line from the "cvs co -c" patch

---
 git-cvsserver.perl              |   34 ++++++++++++++++++++--------------
 t/t9400-git-cvsserver-server.sh |   18 ++++++++++++++++++
 t/t9600-cvsimport.sh            |    1 +
 3 files changed, 39 insertions(+), 14 deletions(-)