Add RLE encoding to the list of encodings when writing metadata

[sadikovi]

This PR adds level encoding to the list of Thrift encodings, when we write column chunk metadata. I forgot to include it in my previous PR. It looks like there is no enforced order on encodings - every system out there tries writing in whatever order they want, and format does not enforce it. Here we are following parquet-cpp.

Also removed redundant & operations that I forgot to remove in my previous patch.

[sadikovi]

@sunchao Can you review? Thanks.

[coveralls]

Pull Request Test Coverage Report for Build 597

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.0004%) to 95.481%

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Files with Coverage Reduction	New Missed Lines	%
column/writer.rs	4	94.72%
<!--	Total:	4		-->

Totals
Change from base Build 596:	0.0004%
Covered Lines:	12023
Relevant Lines:	12592

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💛 - Coveralls