cmd_pull didn't support --squash correctly.
cmd_pull didn't support --squash correctly.

We should implement it as
	git fetch ...
	git subtree merge ...

But we were instead just calling
	git pull -s subtree ...

because 'git subtree merge' used to be just an alias for 'git merge -s
subtree', but it no longer is.

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git