Roll FreeType to 2.6.1 + 1.

Immediately after the VER-2-6-1 release is a desired bugfix.
Roll to get it.

List of changes can be seen at:
https://chromium.googlesource.com/chromium/src/third_party/freetype2/+log/8cabd919ca..30fe5e762e06

BUG=chromium:534621

Review URL: https://codereview.chromium.org/1394513002

Cr-Commit-Position: refs/heads/master@{#352851}