foamFormatConvert compresses boundary file in v1906 (all other utilities leave it uncompressed)

In order to take advantage of the SPDP solver precision, I am using ascii format. When using writeCompression on, snappyHexMesh, renumberMesh, insideCells, etc. compress/gzip all the files in processor*/constant/polyMesh/ EXCEPT boundary, which is always left uncompressed. This is convenient as boundary can be parsed for scripted setup of cases.

foamFormatConvert however, compresses the boundary file. Testing is easy, in controlDict just set: writeFormat ascii; writeCompression on;

and run: foamFormatConvert -constant

Obviously the workaround is simple and it's a minor issue. But consistency is always nice :-)

## Reattaching the author to the issue ticket: @wyldckat ##