Cut mstch manifest

Summary: [OpenSource] Cut `mstch` manifest, which was but is no longer used by `fbthrift`.

Reviewed By: avalonalex, davidtgoldblatt

Differential Revision: D17160816

fbshipit-source-id: 3b96142455d6990870e8ed3e5ce330d339d5a657

build/fbcode_builder/manifests/fboss

@@ -18,7 +18,6 @@ folly
 fb303
 wangle
 rsocket-cpp
-mstch
 fizz
 fmt
 libsodium

build/fbcode_builder/manifests/mstch

-[manifest]
-name = mstch
-
-[download]
-url = https://github.com/no1msd/mstch/archive/1.0.2.tar.gz
-sha256 = 811ed61400d4e9d4f9ae0f7679a2ffd590f0b3c06b16f2798e1f89ab917cba6c
-
-[build]
-builder = cmake
-subdir = mstch-1.0.2
-
-[dependencies]
-boost