servo: Merge #1328 - Work around Rust bug causing nondeterministic CS…

…S parse failure (from kmcallister:properties); r=jdm

The bug is rust-lang/rust#10683 and there's no fix yet, plus it would take us a while to upgrade Rust anyway.

Fixes #1258.

Source-Repo: https://github.com/servo/servo
Source-Revision: 148d1720e539c36ed44efdc7ebf3e45f25388f13

UltraBlame original commit: 28bc03c8fa39fea27af15f247cb7cc3c3f6fe31d

servo/src/components/style/properties.rs.mako

@@ -6907,12 +6907,29 @@ PropertyDeclaration
 >
 PropertyDeclarationParseResult
 {
-match
+/
+/
+FIXME
+:
+local
+variable
+to
+work
+around
+Rust
+#
+10683
+let
+name_lower
+=
 name
 .
 to_ascii_lower
 (
 )
+;
+match
+name_lower
 .
 as_slice
 (