autoroller: Use 10 characters for shortened Git hashes.
autoroller: Use 10 characters for shortened Git hashes.

Recently, the shortened hash
https://chromium.googlesource.com/chromium/src/+/355fabf
was not suffucient for the Chromium repo. Adding three more
should reduce the chance of this happening by 16^3.

NOTRY=True

Review URL: https://codereview.webrtc.org/1841563004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12156}

TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc