Add gerrit settings

Make it simple to setup and use this repo with 'git review' command.

Change-Id: Ic97dda1950689ed86dcf01a49a0894aedaf57bab
diff --git a/.gitreview b/.gitreview
new file mode 100644
index 0000000..b575bb3
--- /dev/null
+++ b/.gitreview
@@ -0,0 +1,3 @@
+[gerrit]
+host=gerrit.osmocom.org
+project=libsmpp34