Minor cleanups of numeric seeded hashing patch.

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
===================================================================
--- src/mips/code-stubs-mips.cc	(revision 10365)
+++ src/mips/code-stubs-mips.cc	(working copy)
@@ -5927,7 +5927,7 @@
                                     Register hash,
                                     Register character) {
   // hash = seed + character + ((seed + character) << 10);
-  __ LoadRoot(hash, Heap::kStringHashSeedRootIndex);
+  __ LoadRoot(hash, Heap::kHashSeedRootIndex);
   // Untag smi seed and add the character.
   __ SmiUntag(hash);
   __ addu(hash, hash, character);