PR #844 breaks PBR rendering

[TRBlount]

After doing some checking via git bisect, PBR ships aren't being rendered correctly after the merge of #844.
This was first brought up in the HTL Leviathan thread. It appears to be that ships aren't rendering the PBR related maps and instead ships with PBR textures get treated as only having diffuse, normal, and glow.

[niffiwan]

From Coverity 1363381; could this be the root cause?

CID 1363381 (#1 of 1): Arguments in wrong order (SWAPPED_ARGUMENTS)swapped_arguments: The positions of arguments in the call to get_shader_hash do not match the ordering of the parameters:

    frag_content is passed to geom_content
    geom_content is passed to frag

https://github.com/scp-fs2open/fs2open.github.com/blob/master/code/graphics/opengl/gropenglshader.cpp#L566

[asarium]

No, that's actually my fault but it doesn't cause this issue. I'll fix is ASAP.

[asarium]

The new material code does not set the ambient occlusion map but even after fixing that the PBR models are still black.

[TRBlount]

Found some interesting things.
-reflect and -shine included, which is almost correct:

only -reflect:

only -shine:

Does this help at all?