Linearise the the commit history before rebasing
Linearise the the commit history before rebasing

Attempt to remove any merge commits of alternative history so that we
can construct a branch containing the local changes starting with the
last import without any special merge commits. If this works we can then
attempt to rebase the branch onto the base commit that will form the new
import. Failures at this point, where the user aborts, will result in
them being returned to a branch, where they can attempt to manually
perform the previous rebase in a interactive mode and attempt to
manipulate the list of commits by hand.

Change-Id: Ic789fc7023b3031b9fd6f73816784524d61d8b2c
JIRA: CICD-733

stackforge/git-upstream,dguerri/git-upstream-old,emonty/git-upstream,dguerri/git-upstream-old,stackforge/git-upstream,emonty/git-upstream