It is cleaner this way since in Win32 console, the
value is always "dumb" while in msysgit it is always
"msys" The user shouldn't change the value of $TERM
in msysgit otherwise their whole copy of msysgit
will be flaky.

BUG=70548
TEST=check $TERM in windows

Review URL: http://codereview.chromium.org/6686027

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@77954 0039d316-1c4b-4281-b951-d872f2087c98