Reconnect when MySQL connection is lost.

BUG=chromium:733103
TEST=bin/run_tests && bin/run_yapf -i && bin/run_lint

Change-Id: I2c95b6405c6658a21f865c0ec7f3741f890e7ab0
Reviewed-on: https://chromium-review.googlesource.com/689394
Commit-Ready: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
1 file changed