[jhbuild] Disable escape sequences in EWS output
https://bugs.webkit.org/show_bug.cgi?id=127922

Reviewed by Alexey Proskuryakov.

* Scripts/webkitpy/common/system/environment.py:
(Environment.disable_gcc_smartquotes):
(Environment):
(Environment.disable_jhbuild_VT100_output):
* Scripts/webkitpy/tool/commands/download_unittest.py:
* Scripts/webkitpy/tool/steps/build.py:
(Build.build):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@163167 268f45cc-cd09-0410-ab3c-d52691b4dbfc