Fix build with buck in Gerrit tree

Since previous version, buck build in Gerrit tree fails
because no rule is provided to generate asciidoctor licence.
The error is:
No rule found when resolving target //lib:LICENSE-asciidoctor

As the licence is available in the lib folder, this fix
simply toggles on the "local_license" option for asciidoctor.

It seems buck build is deprecated now but this fix may
interest people still using Gerrit 2.11

Change-Id: I939eccaa6434602c9ea8b5e479136b7b93234fc9

lib/asciidoctor/BUCK

diff --git a/lib/asciidoctor/BUCK b/lib/asciidoctor/BUCK
index 0b23fdf..63e0cab 100644
--- a/lib/asciidoctor/BUCK
+++ b/lib/asciidoctor/BUCK
@@ -17,6 +17,7 @@
   id = 'org.asciidoctor:asciidoctorj:1.5.4.1',
   sha1 = 'f7ddfb2bbed2f8da3f9ad0d1a5514f04b4274a5a',
   license = 'asciidoctor',
+  local_license = True,
   attach_source = False,
 )