Fix slang option -emit-llvm

b/20671381

Produce .ll file instead of .bc.

Change-Id: I26749e0e64f313b77e9a08fe4579803382795dc5
diff --git a/llvm-rs-cc.cpp b/llvm-rs-cc.cpp
index 0b42894..4730710 100644
--- a/llvm-rs-cc.cpp
+++ b/llvm-rs-cc.cpp
@@ -160,7 +160,7 @@
 
     const char *BCOutputFile = DetermineOutputFile(Opts.mBitcodeOutputDir,
                                                    PathSuffix, InputFile,
-                                                   slang::Slang::OT_Bitcode,
+                                                   Opts.mOutputType,
                                                    *SavedStrings);
     const char *OutputFile = BCOutputFile;