Remove unused rocksdb arcanist lib

Differential Revision: D5470179

fbshipit-source-id: 475ad3b6a85ead5f8abddefddc607353ea8680af

.deprecated_arcconfig

@@ -1,17 +0,0 @@
-{
-  "project_id" : "rocksdb",
-  "conduit_uri" : "https://phabricator.fb.com/api/",
-  "copyright_holder" : "Facebook",
-  "load" : [
-    "arcanist_util"
-  ],
-  "lint.engine" : "FacebookFbcodeLintEngine",
-  "lint.engine.single.linter" : "FbcodeCppLinter",
-  "unit.engine" : "FacebookFbcodeUnitTestEngine",
-  "arcanist_configuration" : "FacebookArcanistConfiguration",
-  "base" : "git:HEAD^, hg:.^",
-  "git.default-relative-commit" : "HEAD^",
-  "git:arc.feature.start.default" : "origin/master",
-  "arc.feature.start.default" : "master",
-  "history.immutable" : false
-}