fix 2 important bugs in configuration parsing

[stdweird]

No description provided.

[stdweird]

@boegel these need to go in, should fix issues reported by @ajdecon, everyone is affected by one of the 2 issues

[boegel]

Does this render #556 useless (except for the unit tests)?

Will this fix the use of $EASYBUILDPREFIX as well?

[boegel]

Apparently it also fixes the issue w.r.t. supporting the legacy way of configuring EasyBuild.

@stdweird: Can you briefly explain why you need the update? This fix is a lot cleaner than what I was doing in #556...

[boegel]

All unit tests pass, which includes the tests for config:

.........................................................
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Ran 57 tests in 189.957s

OK

[boegel]

This clearly fixes the problems, so merging it in.

I'm going to clean up #556 to make it only about the unit tests added there...

[stdweird]

@boegel without the update, the complete old easybuild_config.py was ignored as the olstyle naming was not converted. there is no prefix issue.