Comment change in codereview.settings

gcl is long deprecated, "git cl" is what this is used for now.

TBR: davidben
Change-Id: I5980b8ff3a7c384f4650e195eb6e4daf52da5ae2
Reviewed-on: https://boringssl-review.googlesource.com/30064
Reviewed-by: Ryan Tseng <hinoka@google.com>

codereview.settings

@@ -1,4 +1,4 @@
-# This file is used by gcl to get repository specific information. 
+# This file is used by "git cl" to get repository specific information.
 GERRIT_HOST: True
 GERRIT_PORT: True
 CODE_REVIEW_SERVER: https://boringssl-review.googlesource.com