PHOENIX-5167: fix some LGTM alerts

[malcolmtaylor]

trafficstars

Fix some of the alerts:

• Type mismatch on container access in MetaDataClient and TupleProjectionCompiler
• Type mismatch on container modification in ServerCacheClient
• Equals does not inspect argument type in Column
• Equals on incomparable types in SubselectRewriter, MultiHfileOutputFormat and GuidePostsInfo
• Missing format argument in BaseEventSerializer
• Reference equality on boxed types in ColumnInfo (twice), ArrayFillFunction and PArrayDataType

[malcolmtaylor]

@swaroopak thanks for reviewing. I have rebased to fix the delete/modify conflict.

[swaroopak]

@karanmehta93 @abhishek-chouhan Could you please commit this? Thanks.

[malcolmtaylor]

Rebased