better installation scripts

src/main/deb/postinst

@@ -6,15 +6,26 @@ if id "${config.user}" &>/dev/null; then
 else
     useradd -m ${config.user}
     echo "User '${config.user}' created."
+fi
+
+if ! getent group ${config.group} > /dev/null; then
+    groupadd ${config.group}
+    echo "Group '${config.group}' created."
+fi
 
-    if ! getent group ${config.group} > /dev/null; then
-        groupadd ${config.group}
-        echo "Group '${config.group}' created."
-    fi
+if [ $(getent group dialout) ]; then
+    usermod -a -G dialout ${config.user}
+fi
 
-    usermod -aG dialout,plugdev ${config.user}
+if [ $(getent group plugdev) ]; then
+    usermod -a -G plugdev ${config.user}
 fi
 
+if [ $(getent group systemd-journal) ]; then
+    usermod -a -G systemd-journal ${config.user}
+fi
+
+
 chown -R ${config.user}:${config.group} ${config.installDir} /usr/share/java/r2cloud/*.jar
 chmod 640 ${config.installDir}/lib/*.jar /usr/share/java/r2cloud/*.jar
 
@@ -58,10 +69,6 @@ if [ -f /etc/sudoers.d/nginx ]; then
 	chmod 440 /etc/sudoers.d/nginx
 fi
 
-if [ $(getent group systemd-journal) ]; then
-    usermod -a -G systemd-journal ${config.user}
-fi
-
 if [ ! -d /var/log/journal ]; then
     echo "enable persistent journald logs"
     mkdir -p /var/log/journal

src/main/deb/prerm

@@ -1,2 +1,2 @@
 echo "removing libs..."
-rm ${config.installDir}/lib/*.jar
+rm -f ${config.installDir}/lib/*.jar