[common] Fix algorithm download

The download was using the current user to build the URL
which is not correct since the user may not be the owner.

Fixes #77
4 jobs for 77_fix_cxx_algorithm_download in 9 minutes and 22 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #216929
docker-build
build_linux_36

00:03:02

59.0%
passed #216930
docker-build
build_linux_37

00:02:59

59.0%
passed #216927
macosx
build_macosx_36

00:09:22

59.0%
passed #216928
macosx
build_macosx_37

00:09:08

59.0%