Copy description from Cargo.toml to METADATA

Test: make
Change-Id: I05f47617c05b4dff6ed2832768be1447e446c31a
diff --git a/METADATA b/METADATA
index 4500ae0..5029778 100644
--- a/METADATA
+++ b/METADATA
@@ -1,5 +1,5 @@
 name: "syn-mid"
-description: "Providing the features between \'full\' and \'derive\' of syn."
+description: "Providing the features between \"full\" and \"derive\" of syn."
 third_party {
   url {
     type: HOMEPAGE