Stop using default bam_readcount_version

This is necessary to get a new snapshot out. Recently, the default bam_readcount_version was incremented to 0.6. Many tools did not specify (or specified optionally) the version, and thus relied on the default.

Processing profiles for both phenotype correlation and clinseq have been backfilled to use bam-readcount 0.4.
Is this supposed to be optional?