Remove direct zlib dep

Summary: moxygen doesn't use zlib.  proxygen does if you install a compression filter.

Reviewed By: sandarsh

Differential Revision: D93503603

fbshipit-source-id: 85c29d16c87b96385bdb243e339b190cdf21ae13

Author: afrind

build/fbcode_builder/manifests/moxygen

@@ -23,7 +23,6 @@ BUILD_TESTS = ON
 BUILD_TESTS = OFF
 
 [dependencies]
-zlib
 gperf
 folly
 fizz