ADT/SparseMultiSetTest.cpp: Try to appease cygwin-clang on stage2, take two. [-Wsign-compare]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173144 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/ADT/SparseMultiSetTest.cpp b/unittests/ADT/SparseMultiSetTest.cpp
index d8999ca..032990e 100644
--- a/unittests/ADT/SparseMultiSetTest.cpp
+++ b/unittests/ADT/SparseMultiSetTest.cpp
@@ -175,7 +175,7 @@
   USet::iterator E = RangePair.second;
 
   // Move the iterators around, going to end and coming back.
-  EXPECT_EQ(3u, std::distance(B, E));
+  EXPECT_EQ(3, std::distance(B, E));
   EXPECT_EQ(B, --(--(--E)));
   EXPECT_EQ(++(++(++E)), Set.end());
   EXPECT_EQ(B, --(--(--E)));