Fix field name of OAuthTokenProto.provider_id
Fix field name of OAuthTokenProto.provider_id

This is a trivial proto change which doesn't even affect the generated
code.

Change-Id: I823054400ce068102443a1f6bc3d9ea175642b72

qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,WANdisco/gerrit