ensure utf-8 encoding when processing commit message

Review Request #10520 — Created April 8, 2019 and discarded — Latest diff uploaded




The rbt post command fails to post review with error

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 57: ordinal not in range(128)

When commit message has a unicode char, for example:
TlsOverhead.callOpNull true thrpt 25 12865.357 ± 135.963 ops/s

Afer localy patching the rbtool I was able to post the review into our RB server.