Update buck version to same as Gerrit

Change-Id: I4248ea76b2c02a13d90da7860fc30eb2b6eecba6

buckversion

diff --git a/buckversion b/buckversion
index 05c1944..b37000e 100644
--- a/buckversion
+++ b/buckversion
@@ -1 +1 @@
-e8190a34ff10bdb55729a8a50669805f833f6a85
+c60dc12b3280d19dc9e531b137e911c95760fc8f