master Yesod needed specific versions

yesod/bench/bench.cabal

@@ -18,7 +18,8 @@ executable         bench
                 EmptyDataDecls
 
     build-depends: base                          >= 4          && < 5
-                 , yesod                         >= 1.2        && < 1.3
+                 , yesod                         == 1.2.2
+                 , yesod-core                    == 1.2.4
                  , text                          >= 0.11       && < 0.12
                  , persistent                    >= 1.2        && < 1.3
                  , persistent-mysql              >= 1.2        && < 1.3