Patches should be submitted to master, not maint

Update SUBMITTING_PATCHES accordingly.

Change-Id: I6fd57a84c67d3762f1f23276d95cac2aeecd5e8f
diff --git a/SUBMITTING_PATCHES b/SUBMITTING_PATCHES
index 63b0e57..cba6741 100644
--- a/SUBMITTING_PATCHES
+++ b/SUBMITTING_PATCHES
@@ -5,7 +5,7 @@
  - Make sure all code is under the Apache License, 2.0.
  - Publish your changes for review:
 
-   git push https://gerrit-review.googlesource.com/git-repo HEAD:refs/for/maint
+   git push https://gerrit-review.googlesource.com/git-repo HEAD:refs/for/master
 
 
 Long Version:
@@ -71,7 +71,7 @@
 a remembered remote to make this easier in the future:
 
    git config remote.review.url https://gerrit-review.googlesource.com/git-repo
-   git config remote.review.push HEAD:refs/for/maint
+   git config remote.review.push HEAD:refs/for/master
 
    git push review