Ensure 'sogo' UNIX group exists at installation

Previous logic only checked for user existence.

packaging/debian-multiarch/sogo.preinst

@@ -13,8 +13,8 @@ set -e
 
 if [ "$1" == "install" ] || [ "$1" == "upgrade" ]; then
 
+  getent group sogo >& /dev/null || groupadd -f -r sogo
   if ! id sogo 1> /dev/null 2>&1; then
-    groupadd -f -r sogo
     useradd -d /var/lib/sogo -g sogo -c "SOGo daemon" -s /usr/sbin/nologin -r sogo
   fi
 

packaging/debian/sogo.preinst

@@ -13,8 +13,8 @@ set -e
 
 if [ "$1" == "install" ] || [ "$1" == "upgrade" ]; then
 
+  getent group sogo >& /dev/null || groupadd -f -r sogo
   if ! id sogo 1> /dev/null 2>&1; then
-    groupadd -f -r sogo
     useradd -d /var/lib/sogo -g sogo -c "SOGo daemon" -s /usr/sbin/nologin -r sogo
   fi
 

packaging/rhel/sogo.spec

@@ -388,6 +388,9 @@ rm -fr ${RPM_BUILD_ROOT}
 
 # **************************** pkgscripts *****************************
 %pre
+if ! getent group %sogo_user >& /dev/null; then
+  groupadd -f -r %sogo_user
+fi
 if ! id %sogo_user >& /dev/null; then
   /usr/sbin/useradd -d %{_var}/lib/sogo -c "SOGo daemon" -s /sbin/nologin -M -r %sogo_user
 fi