pr-syntax-check - install all requirements

pr-syntax-check - install all requirements

This change removes the grep for 'ansible' when installing
requirements in ceph-ansible-pr-syntax-check. The grep
cause onlye the ansible requirement to be installed, ignoring
the other packages. This causes an issue in PR[1] which
introduce a filter plugin that depend on the netaddr package.

[1] https://github.com/ceph/ceph-ansible/pull/4339

Closes: #1390
Signed-off-by: Harald Jensås <hjensas@redhat.com>