Polygerrit abbreviation algorithm deviates from the GWT UI. It removes
all low case letters and dashes. This produces different abbreviation
string. Most prominent example is different computed label shortcut
for PolyGerrit-Review label: PGR instead of PR in GWT UI. Align the
abbreviation on Polygerrit side with GWT algorithm, that tokenizes
the label name with dash as delimiter and concatenates the upper cased
first character of each token.
Bug: Issue 6529
Change-Id: Ib5ef1448df84c5933c549777e55bf7869bfcfc33
2044ea882f