Bump llvm-rs-cc version number to 1901.

BUG: 12135682
https://code.google.com/p/android/issues/detail?id=64775

This is to ensure that we can recognize tools that have the fix for encoding
bitcode attributes like readnone/readonly on parameters (i.e. we strip it).

Change-Id: I303c0c730c66706425289c6dc7d494dcb075120d
diff --git a/slang_version.h b/slang_version.h
index e42f1a5..13c55d8 100644
--- a/slang_version.h
+++ b/slang_version.h
@@ -49,7 +49,8 @@
   JB_MR1 = 1700,
   JB_MR2 = 1800,
   KK = 1900,
-  CURRENT = KK
+  KK_P1 = 1901,
+  CURRENT = KK_P1
 };
 }  // namespace SlangVersion