--- a/testing/geckodriver/build.rs
+++ b/testing/geckodriver/build.rs
@@ -27,25 +27,25 @@ fn main() {
     writeln!(
         fh,
         "const COMMIT_DATE: Option<&'static str> = {:?};",
         commit_date()
     ).unwrap();
 }
 
 fn commit_hash() -> Option<String> {
-    exec(&"hg", &["log", "-r.", "-T '{node|short}'"]).or_else(
+    exec(&"hg", &["log", "-r.", "-T{node|short}"]).or_else(
         || {
             exec(&"git", &["rev-parse", "HEAD"]).and_then(hg2git_sha)
         },
     )
 }
 
 fn commit_date() -> Option<String> {
-    exec(&"hg", &["log", "-r.", "-T '{date|isodate}'"]).or_else(|| {
+    exec(&"hg", &["log", "-r.", "-T{date|isodate}"]).or_else(|| {
         exec(
             &"git",
             &["log", "-1", "--date=short", "--pretty=format:%cd"],
         )
     })
 }
 
 fn exec<S, I>(program: S, args: I) -> Option<String>