SPV Version: Emit the requested SPIR-V version, not the header version.

Fixes #1236.
diff --git a/SPIRV/GlslangToSpv.cpp b/SPIRV/GlslangToSpv.cpp
index ce5e369..64bce35 100755
--- a/SPIRV/GlslangToSpv.cpp
+++ b/SPIRV/GlslangToSpv.cpp
@@ -107,7 +107,8 @@
 //
 class TGlslangToSpvTraverser : public glslang::TIntermTraverser {
 public:
-    TGlslangToSpvTraverser(const glslang::TIntermediate*, spv::SpvBuildLogger* logger, glslang::SpvOptions& options);
+    TGlslangToSpvTraverser(unsigned int spvVersion, const glslang::TIntermediate*, spv::SpvBuildLogger* logger,
+        glslang::SpvOptions& options);
     virtual ~TGlslangToSpvTraverser() { }
 
     bool visitAggregate(glslang::TVisit, glslang::TIntermAggregate*);
@@ -880,13 +881,13 @@
 // Implement the TGlslangToSpvTraverser class.
 //
 
-TGlslangToSpvTraverser::TGlslangToSpvTraverser(const glslang::TIntermediate* glslangIntermediate,
+TGlslangToSpvTraverser::TGlslangToSpvTraverser(unsigned int spvVersion, const glslang::TIntermediate* glslangIntermediate,
                                                spv::SpvBuildLogger* buildLogger, glslang::SpvOptions& options)
     : TIntermTraverser(true, false, true),
       options(options),
       shaderEntry(nullptr), currentFunction(nullptr),
       sequenceDepth(0), logger(buildLogger),
-      builder((glslang::GetKhronosToolId() << 16) | glslang::GetSpirvGeneratorVersion(), logger),
+      builder(spvVersion, (glslang::GetKhronosToolId() << 16) | glslang::GetSpirvGeneratorVersion(), logger),
       inEntryPoint(false), entryPointTerminated(false), linkageOnly(false),
       glslangIntermediate(glslangIntermediate)
 {
@@ -6067,7 +6068,7 @@
 
     glslang::GetThreadPoolAllocator().push();
 
-    TGlslangToSpvTraverser it(&intermediate, logger, *options);
+    TGlslangToSpvTraverser it(intermediate.getSpv().spv, &intermediate, logger, *options);
     root->traverse(&it);
     it.finishSpv();
     it.dumpSpv(spirv);