Upgrade buck to gerrit/410fcf34

Buck upstream now supports a daemon mode[1] which allows BUILD
files to be cached across invocations. This saves considerable
time on startup, especially for no-op incremental builds:

  no-op without buckd:  10.6s
  no-op with    buckd:   5.2s

However the current daemon implementation is insecure. Users
should only run it on dedicated machines where they trust all
other running processes.

Buck now requires Java 7. If it is missing the build will fail.

[1] http://facebook.github.io/buck/command/buckd.html
Change-Id: I55dec63e467f8f4db5a799296fb7f588ce4b2aa1

.buckversion

@@ -1 +1 @@
-b01f03b82e23614965c2ddc13900ccc6dc4d8361
+410fcf3420cb06e62cbe9ee93eff931fa9a9b1a2

.gitignore

@@ -7,5 +7,7 @@
 /gerrit-parent.iml
 *.sublime-*
 /gerrit-package-plugins
+/.buckconfig.local
+/.buckd
 /buck-out
 /local.properties