[sanitizer] update the list of supported platforms in the docs

llvm-svn: 200529
diff --git a/clang/docs/MemorySanitizer.rst b/clang/docs/MemorySanitizer.rst
index 5fc7e74..f769cc9 100644
--- a/clang/docs/MemorySanitizer.rst
+++ b/clang/docs/MemorySanitizer.rst
@@ -157,7 +157,7 @@
 
 MemorySanitizer is supported on
 
-* Linux x86\_64 (tested on Ubuntu 10.04 and 12.04);
+* Linux x86\_64 (tested on Ubuntu 12.04);
 
 Limitations
 ===========