Copy description from Cargo.toml to METADATA

Test: make
Change-Id: I5f2ba2e7c41761d8012125d069da55b0c7e2b39f
diff --git a/METADATA b/METADATA
index 43064d9..321ce13 100644
--- a/METADATA
+++ b/METADATA
@@ -1,5 +1,5 @@
 name: "protobuf-codegen"
-description: "Code generator for rust-protobuf.\n\nIncludes a library and `protoc-gen-rust` binary.\n\nSee `protoc-rust` and `protobuf-codegen-pure` crates.\n"
+description: "Code generator for rust-protobuf.  Includes a library and `protoc-gen-rust` binary.  See `protoc-rust` and `protobuf-codegen-pure` crates."
 third_party {
   url {
     type: HOMEPAGE