Use current branch in 'make distcheck'

Submitted by ema-pe

Assigned to Sean Davis @bluesabre

Link to original bug (#16859)

Description

From Gitlab merge request: !3 (merged)

Actually 'make distcheck' always create the gzipped file of 'master' branch. This is not correct when I am on a different branch.

This merge request allow the creation of zipped distribution file using the current branch calling git branch --show-current.