DX11: Fix ClearScreen properly this time. Should fix quite a few games (or break them :P)

Fixes issue 3399.

Also remove unnecessary stateman/gfxstate applies:
- gfxstate->ApplyState/Reset only need to be called by VertexManager
- stateman->Apply only needs to be called before any Draw/DrawIndexed call

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6309 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Plugins/Plugin_VideoDX11/Src/D3DUtil.cpp

@@ -673,6 +673,7 @@ void drawColorQuad(u32 Color, float x1, float y1, float x2, float y2)
 	context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
 	context->IASetVertexBuffers(0, 1, &util_vbuf->GetBuffer(), &stride, &offset);
 
+	stateman->Apply();
 	context->Draw(4, cq_offset);
 }