[Postcompiler] Not packing all textures that exists in the .vmt files

[nikita488]

It seems that postcompiler tries to find and pack textures from the root level of .vmt file ignoring section for other shaders. In this case only textures that was found in "LightMappedGeneric" section was found and packed, detail_concrete_01, concrete_modular_wall001a_height-ssbump and concrete_modular_wall001a_normal was not packed because they are in the separate shader sections.

"LightMappedGeneric"
{
	"$basetexture"	"concrete/concrete_bts_modular_wall001a"
	"$surfaceprop" "concrete"
	"%keywords" "portal"

	"LightmappedGeneric_HDR_DX9"
	{
		"$bumpmap" "concrete/concrete_modular_wall001a_height-ssbump"
		"$ssbump" "1"

        	"$detail" "detail\detail_concrete_01"
		"$detailscale" "4.25"
		"$detailblendfactor" .35
		"$detailblendmode" 0
	}

	"LightmappedGeneric_DX9"
	{
		"$bumpmap" "concrete/concrete_modular_wall001a_height-ssbump"
		"$ssbump" "1"

        	"$detail" "detail\detail_concrete_01"
		"$detailscale" "4.25"
		"$detailblendfactor" .35
		"$detailblendmode" 0
	}

	"LightmappedGeneric_DX8"
	{
		"$bumpmap" "concrete/concrete_modular_wall001a_normal"
		"$nodiffusebumplighting" 1
	}

	"LightmappedGeneric_NoBump_DX8"
	{
		"$basetexture" "Concrete/concrete_bts_modular_wall001a"
		"$basealphaenvmapmask" 1
	}
}