gitconfig: preserve is deprecated. use merges. fix #158
gitconfig: preserve is deprecated. use merges. fix #158

see https://stackoverflow.com/questions/15915430/what-exactly-does-gits-rebase-preserve-merges-do-and-why

tobiipro/support-firecloud,tobiipro/support-firecloud,tobiipro/support-firecloud,tobiipro/support-firecloud