Previously, when calling rbt land -S, the call to rbt patch would

not respect the -S flag and instead would use whatever behaviour was

default (i.e., defaulting to using history). Now this has been

rectified so that rbt land explicitly gives rbt patch either the

-S or -H flags.

Ran unit tests.
Landed a review request with commit history and used the -S flag.

Verified that the review request was patched as a squashed review

request.