Add third_party/colorama to DEPS

In the chromium_revision DEPS roll CL
https://review.webrtc.org/12729004/ (r6516) the addition
of the third_party/colorama was missed since our trybots
currently cannot handle DEPS changes in tryjob patches
properly.
Adding third_party/colorama/src fixes the Android build.

TEST=Passing local compile with GYP_DEFINES="OS=android component=static_library fastbuild=1 target_arch=arm"
TBR=andrew@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/12819004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6517 4adac7df-926f-26a2-2b94-8c16560cd09d