[PATCH v2 1/3] t/gitweb-lib.sh: print to stderr when gitweb_run has errors

Change the gitweb_run test subroutine to spew errors to stderr if there are any, previously it would just silently fail, which made tests very hard to debug.

Before you'd get this output, when running tests under `--verbose --immediate --debug`:

    expecting success: git rm renamed_file &&
             rm -f renamed_file &&
             git commit -a -m "File removed." &&
             gitweb_run "p=.git;a=commitdiff"
    rm 'renamed_file'
    [master 8d80741] File removed.
     Author: A U Thor <author@example.com>
     1 files changed, 0 insertions(+), 1 deletions(-)
     delete mode 120000 renamed_file
    not ok - 32 commitdiff(0): file deleted
    #       git rm renamed_file &&
    #                rm -f renamed_file &&
    #                git commit -a -m "File removed." &&
    #                gitweb_run "p=.git;a=commitdiff"

Now you'll get the much more useful:

    expecting success: git rm renamed_file &&
             rm -f renamed_file &&
             git commit -a -m "File removed." &&
             gitweb_run "p=.git;a=commitdiff"
    rm 'renamed_file'
    [master 2a4214e] File removed.
     Author: A U Thor <author@example.com>
     1 files changed, 0 insertions(+), 1 deletions(-)
     delete mode 120000 renamed_file
    [Sat Feb 19 14:32:54 2011] gitweb.perl: Use of uninitialized value in subroutine entry at /home/avar/g/git/t/../gitweb/gitweb.perl line 4415.
    not ok - 32 commitdiff(0): file deleted
    #       git rm renamed_file &&
    #                rm -f renamed_file &&
    #                git commit -a -m "File removed." &&
    #                gitweb_run "p=.git;a=commitdiff"
---
 t/gitweb-lib.sh |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)