Buck: Upgrade to the latest version

Since [1] genrule() target doesn't accept deps parameters any more.
As replacement, cmd should use $(location :foo) macro. Reshuffle some
rules to fix existing genrule targets. Remove all rule, as it cannot
depend any more on api and release. Moreover create all.zip with both
api.zip and release.war included doesn't make really sense. Adjust the
documentation correspondingly.

gen_licences.py is accepting first order dependencies and computes the
classpath on its own. Make it work for now by passing the classpath for
the dependencies.  Add a TODO to clean this up and accept the classpath
from the Buck side, similar to what was done in Ifd2dcf69aa.

[1] https://github.com/facebook/buck/commit/d2c6edbf7b41ee5662902c1f06f570fa4bc8e005

Change-Id: Iab403cd964d09aff652662cd18b020db8e07a0d9
diff --git a/README.md b/README.md
index 573042d..f5b929d 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@
 Install [Buck](http://facebook.github.io/buck/setup/install.html) and run the following:
 
         git clone --recursive https://gerrit.googlesource.com/gerrit
-        cd gerrit && buck build all
+        cd gerrit && buck build release
 
 ## Install binary packages (Deb/Rpm)