Description of problem:

The bash completions for dnf commands are contaminated with a bunch of non-command strings, which look like pieces of a diagnostic or deprecation message that has been parsed into potential completions

Version-Release number of selected component (if applicable):

dnf-1.1.9-1.fc23.noarch

How reproducible:

Always

Steps to Reproduce:
1. type 'dnf' plus a space, and press tab twice to get the completions
2. see the nonsense entries mixed into the completions
3.

Actual results:

# dnf 
a                             list
and                           makecache
API                           mark
at                            needs-restarting
autoremove                    not
available                     of
be                            officially
builddep                      only
check-update                  part
clean                         playground
config-manager                Please
copr                          'plugins'
debuginfo-install             provides
distribution-synchronization  reinstall
distro-sync                   release.
DNF                           remove
documentation                 removed
<snip snip>

Expected results:

The completions should only include dnf operations. Here is the result from an old machine with an old (dnf-0.6.4-7.fc21.noarch) version of dnf:

$ dnf 
autoremove           makecache             
check-update         provides              
clean                reinstall             
distro-sync          remove
downgrade            repolist
<snip snip>

Additional info:

Looks like a diagnostic or deprecation message is being misparsed to form the completion list. I'm not sure if this is the fault of dnf; it may be that this should be assigned to bash-completion instead.