ceph.spec.in: remove build directory in %clean, not %install

Removing the build directory at the end of %install is too soon,
and means we get rid of a bunch of stuff needed to correctly
create debuginfo/debugsource packages, which happens automatically
right after %install.  So, let's put it where it really belongs, in
the %clean section.

Fixes: aa18cb1
Fixes: https://tracker.ceph.com/issues/55079
Signed-off-by: Tim Serong <tserong@suse.com>
(cherry picked from commit 94ad178)

ceph.spec.in

@@ -1356,13 +1356,12 @@ install -m 644 -D monitoring/prometheus/alerts/ceph_default_alerts.yml %{buildro
 %py_byte_compile %{__python3} %{buildroot}%{python3_sitelib}
 %endif
 
+%clean
+rm -rf %{buildroot}
 # built binaries are no longer necessary at this point,
 # but are consuming ~17GB of disk in the build environment
 rm -rf build
 
-%clean
-rm -rf %{buildroot}
-
 #################################################################################
 # files and systemd scriptlets
 #################################################################################