After upgrading Gerrit to 2.13 our gate stopped working. The reason
for this is that after a successful gate run zuul does something like
'gerrit review --label verified=2 --submit'. The verified label in
Gerrit by default is configured as 'Verified'. The newer version of
gerrit behaves different now. It accepts the +2 vote on verified but
doesn't submit the patch anymore if the casing is not correct. This
forces us to specify the label in the same casing as gerrit
expects. In that case the tolower() in canMerge prevents the patch
from entering the gate.
In order to avoid confusion and be consistent, avoid any case
conversions and use the labels exactly as defined in Gerrit.
Note that this patch requires changes to the pipelines such that the
labels are spelled exactly as defined in Gerrit.
Change-Id: I9713a075e07b268e4f2620c0862c128158283c7c
ea98a194cc