Revert -float-abi implementation.

The new command line option conflicted with a builtin LLVM 3.0
one. The functionality will be added back in after the 0.11.0
release branch has been created.

This reverts commit 6a1bc70bd7 and
subsequent fixes.

driver/main.cpp

@@ -459,9 +459,8 @@ int main(int argc, char** argv)
     if (global.errors)
         fatal();
 
-    gTargetMachine = createTargetMachine(mTargetTriple, mArch, mCPU, mAttrs,
-        bitness, mFloatABI, mRelocModel, mCodeModel, codeGenOptLevel(),
-        global.params.symdebug);
+    gTargetMachine = createTargetMachine(mTargetTriple, mArch, mCPU, mAttrs, bitness,
+        mRelocModel, mCodeModel, codeGenOptLevel(), global.params.symdebug);
     global.params.targetTriple = llvm::Triple(gTargetMachine->getTargetTriple());
 
 #if LDC_LLVM_VER >= 302