Fix the AssertingVH unittests.

llvm-svn: 75060
diff --git a/llvm/lib/VMCore/Value.cpp b/llvm/lib/VMCore/Value.cpp
index 0120333..94bafdf 100644
--- a/llvm/lib/VMCore/Value.cpp
+++ b/llvm/lib/VMCore/Value.cpp
@@ -517,7 +517,7 @@
            << "\n";
 #endif
       LLVM_UNREACHABLE("An asserting value handle still pointed to this"
-                       "value!");
+                       " value!");
     case Weak:
       // Weak just goes to null, which will unlink it from the list.
       ThisNode->operator=(0);
@@ -592,4 +592,3 @@
       setOperand(i, To); // Fix it now...
     }
 }
-