Convert paths in environment variables back to msys-style inside commit-log-editor

Convert paths in environment variables back to msys-style inside commit-log-editor

When this script gets run from inside git commit, msys-style paths in the environment will
have been turned into Windows-style paths with forward slashes. This screws up functions
like File::Spec->rel2abs, which seem to rely on $PWD having an msys-style path. We convert
the paths back to msys-style before doing anything else.

Fixes <http://webkit.org/b/48527> commit-log-editor uses full paths for section headers when
using msysgit's Perl and multiple ChangeLogs have been edited

Reviewed by David Kilzer.

* Scripts/commit-log-editor: Call fixEnvironment before doing anything else.
(fixEnvironment): Added. When run in msys in conjunction with git (i.e., when invoked from
inside git commit), convert Windows-style paths in the environment back to msys-style paths.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@76255 268f45cc-cd09-0410-ab3c-d52691b4dbfc