Add remove attribute procedure to FileMetadata

[bena-nasa]

In the interp_restart code, to produce the output file I "cheat". Basically load the input file and produce a fileMetadata object from it. I then copy this to a new fileMetadata object and change the dimensions in object. Then I can use this to produce the new file.

The problem is that if the input is stretched but the output is not, @wmputman found that the stretching parameters were getting into the output file in his new updated inpterp_restarts.x version that can handle both and input and/or output stretched grid. So I needed a procedure to remove them if needed before writing.

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog

[tclune]

Longer term is there an option to simply pass a correct metadata object when creating the new file? This seems kludgy.