Fix include guard in IpGenAugSystemSolver.hpp

[skeeto]

Appears to be a copy-paste error from IpStdAugSystemSolver.hpp.

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✅ svigerske
❌ skeeto
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[svigerske]

Thank you. Very nice.

Looks like the Appveyor is broken now, but that is unrelated to the change here.

[skeeto]

That was fast! Thanks, Stefan.