exclude candidateSV Manta VCFs from annotation

[maxulysse]

cf #746

According to snpEff docs, snpEff should only work on SNPs, insertions, deletions and MNPs.

• Manta candidateSV are no longer annotated by snpEff by default

PR checklist

• PR is made against dev branch
• This comment contains a description of changes (with reason)
• Ensure the test suite passes (./scripts/test.sh -p docker -t ALL).
• CHANGELOG.md is updated

EDIT: update comments

[maxulysse]

Actually I think that just excluding *candidateSV.vcf files from Manta should be enough.