Don't create the znc user unless use_systemd is set

znc.spec

@@ -109,6 +109,7 @@ chmod -x modules/q.cpp
 %__make %{?_smp_mflags}
 
 %pre
+%if %{use_systemd}
 getent group znc >/dev/null || groupadd -r znc
 getent passwd znc >/dev/null || \
     useradd -r -g znc -d /var/lib/znc -s /sbin/nologin \
@@ -116,6 +117,7 @@ getent passwd znc >/dev/null || \
 mkdir -p /var/lib/znc
 chown znc:znc /var/lib/znc
 exit 0
+%endif
 
 %install
 %__rm -Rf "%{buildroot}"