codereview.settings: stop forcing squashing

There's no reason this needs to be forced on users.  All other
repos have dropped it, and git-cl itself will be dropping it.

Bug: 993518
Change-Id: Ibee07219eee6031046ba1ed5354be5a7b4cb9f82
diff --git a/codereview.settings b/codereview.settings
index 2a3457b..cfb1e06 100644
--- a/codereview.settings
+++ b/codereview.settings
@@ -1,3 +1,2 @@
 CODE_REVIEW_SERVER: https://r8.googlesource.com/
 GERRIT_HOST: True
-GERRIT_SQUASH_UPLOADS: True