Update the eden manifest to drop internal FB-specific dependencies

Summary:
Remove the Facebook-specific dependencies from the Eden manifest: these
dependencies are now available directly in the Eden repository.

Reviewed By: chadaustin

Differential Revision: D18588009

fbshipit-source-id: 590c74e38e4e05939e6955839af3ebb959f9251b

build/fbcode_builder/manifests/eden

@@ -18,6 +18,7 @@ fb303
 cpptoml
 rocksdb
 libgit2
+lz4
 python-toml
 
 # macOS ships with sqlite3, and some of the core system
@@ -36,9 +37,6 @@ osxfuse
 [dependencies.not(os=windows)]
 libcurl
 
-[dependencies.fb=on]
-fb-mercurial
-
 [shipit.pathmap]
 fbcode/eden/oss = .
 fbcode/eden = eden