Update execute metadata query to match API response

[swfree]

Issue Link 🔗

• Fixes bug where BoxResourceIterable<BoxMetadataQueryItem> results = MetadataTemplate.executeMetadataQuery(...) was returning null results

Implementation Details 🚧

• Removed the executeMetadataQuery that returns data as BoxMetadataQueryItem. Decided to remove instead of deprecate since the method does not work and always returns null
• Users should only use the executeMetadataQuery method that returns data as BoxItem.Info

Testing Details 🔍

• Updated unit tests

[sujaygarlanka]

@swfree Just some linting errors that need to be fixed for Travis

[coveralls]

Pull Request Test Coverage Report for Build 2451

• 1 of 4 (25.0%) changed or added relevant lines in 1 file are covered.
• 6 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.2%) to 67.889%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/main/java/com/box/sdk/MetadataTemplate.java	1	4	25.0%

Files with Coverage Reduction	New Missed Lines	%
src/main/java/com/box/sdk/EventStream.java	1	87.63%
src/main/java/com/box/sdk/BoxJSONResponse.java	2	93.33%
src/main/java/com/box/sdk/RealtimeServerConnection.java	3	80.0%

Totals
Change from base Build 2447:	-0.2%
Covered Lines:	6256
Relevant Lines:	9215

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💛 - Coveralls

[swfree]

Thanks @sujaygarlanka! Fixed the linting errors