Buck: Remove jgit cell

Cross cell support in Buck is considered as experimental feature, with
number of open issues: [1], [2], [3].  Moreover, to make Maven Central
machinery work, it was needed to create symbolic links in source tree.
That broke `buck targets` feature.

Remove it for now, and re-consider to add it later.

[1] https://github.com/facebook/buck/issues/656
[2] https://github.com/facebook/buck/issues/658
[3] https://github.com/facebook/buck/issues/717

Bug: Issue 3954
Change-Id: Ic621a07771f926001df181b46b2169e214ce208a

gerrit-gpg/BUCK

@@ -8,8 +8,8 @@ DEPS = [
   '//lib/guice:guice',
   '//lib/guice:guice-assistedinject',
   '//lib/guice:guice-servlet',
+  '//lib/jgit/org.eclipse.jgit:jgit',
   '//lib/log:api',
-  '@jgit//org.eclipse.jgit:jgit',
 ]
 
 java_library(
@@ -50,7 +50,7 @@ java_test(
     '//lib:truth',
     '//lib/bouncycastle:bcpg',
     '//lib/bouncycastle:bcprov',
-    '@jgit//org.eclipse.jgit.junit:junit',
+    '//lib/jgit/org.eclipse.jgit.junit:junit',
   ],
   source_under_test = [':gpg'],
   visibility = ['//tools/eclipse:classpath'],