ceph.spec.in: remove setuptools dependency

in 844b66de, we stopped using pkg_resources for import packaging.
and the exact reason why we introduced pkg_resources was for using
the packaging python module, see cf608920.

so, let's partially revert cf608920.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>

ceph.spec.in

@@ -672,7 +672,6 @@ Group:          System/Filesystems
 Requires:       ceph-mgr = %{_epoch_prefix}%{version}-%{release}
 Requires:       ceph-grafana-dashboards = %{_epoch_prefix}%{version}-%{release}
 Requires:       ceph-prometheus-alerts = %{_epoch_prefix}%{version}-%{release}
-Requires:       python%{python3_pkgversion}-setuptools
 %if 0%{?fedora} || 0%{?rhel} >= 9
 Requires:       python%{python3_pkgversion}-grpcio
 Requires:       python%{python3_pkgversion}-grpcio-tools

debian/ceph-mgr-modules-core.requires

@@ -4,5 +4,4 @@ packaging
 pecan
 werkzeug
 requests
-pkg-resources
 python-dateutil

src/pybind/mgr/requirements-required.txt

@@ -12,7 +12,6 @@ pytest-cov==2.7.1
 pyyaml
 requests-mock
 scipy
-setuptools
 werkzeug
 natsort
 bcrypt