Redmine

As the subject states, the file download button is also displayed on repository directory entries. This obviously shouldn't be the case.
This issue has been introduced with r16672 for #26035.

I'll attach a small patch fixing the issue. I've included the addition of a test assertion (for Git) showcasing the issue. I am not sure what is the best place to test this properly, so I've left multiple of such assertions out of the other adapters.

The patch, against source:/trunk@16749, is produced using git format-patch which makes it apply-able using "patch -p1 < 0001-...".

Environment:

Environment:
  Redmine version                3.4.0.devel@r16749
  Ruby version                   2.3.3-p222 (2016-11-21) [x86_64-linux]
  Rails version                  4.2.8
  Environment                    production
  Database adapter               Mysql2
SCM:
  Subversion                     1.8.8
  Git                            1.9.1
  Filesystem                     
Redmine plugins:
  no plugin installed