[vcs-log, git] turn on index usage for highlighting cherry-picked commits
[vcs-log, git] turn on index usage for highlighting cherry-picked commits

IDEA-177606

allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community,allotria/intellij-community