spec/unit_tests/moab: remove cruft (inspired by rubocop)

[ndushay]

Please review especially for:

• no useful tests removed (some pointless ones have been removed)
• no existing test functionality has been changed (refactored some variable names or avoided long lines or changed otherwise for readability)

This spec cleanup:

• shortens names of specs to be just the method names
• removes comments containing the rdoc or implementation of methods
• removes specs that are useless (e.g. that setting an attribute value means you can retrieve the attribute value; that instantiating an object returns an instance of the object)
• splits out multiple tests in a single spec into separate tests
• avoids long lines
• refactors variable names for clarity
• removes unnecessary @ variables
• tried to follow principles to make rubocop happier
  etc.

Connected to #6

[coveralls]

Coverage decreased (-0.04%) to 99.28% when pulling f27e0df on clean-moab-specs1 into beb7dfa on master.

[coveralls]

Coverage decreased (-0.04%) to 99.276% when pulling 8822b9a on clean-moab-specs1 into 368c74a on master.

[jmartin-sul]

two or three small nitpicks, but looks great overall. definitely an improvement in readability and maintainability, AFAICT.

[jmartin-sul]

probably doesn't make a practical difference since it's empty anyway, but seems like this should use Moab::VersionMetadataEvent.new({}), since the constructor wants a hash?

[jmartin-sul]

seems like this should be a list, like it was previously? e.g. versions: [double(Moab::VersionMetadataEntry.name)]

[jmartin-sul]

this seems duplicative of lines 13-17? if so, i'd be inclined to remove one or the other, though no preference on my part as to which one.

[coveralls]

Coverage decreased (-0.04%) to 99.275% when pulling 8f16289 on clean-moab-specs1 into 368c74a on master.

[coveralls]

Coverage decreased (-0.04%) to 99.275% when pulling 8f16289 on clean-moab-specs1 into 368c74a on master.

[coveralls]

Coverage decreased (-0.04%) to 99.276% when pulling a973abc on clean-moab-specs1 into 368c74a on master.