trac-svn-hook: fix a test which could fail in non-bash shells and add a note for setting TRAC_ENV directly in the hooks.
trac-svn-hook: fix a test which could fail in non-bash shells and add a note for setting TRAC_ENV directly in the hooks.


git-svn-id: 0d96b0c1a6983ccc08b3732614f4d6bfcf9cbb42@9167 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac