Avoid possibly including the same keyserver twice

src/freedombone-adduser

@@ -119,9 +119,14 @@ fi
 # generate a gpg key
 echo "Making a GPG key for $ADD_USERNAME@$HOSTNAME"
 mkdir "/home/$ADD_USERNAME/.gnupg"
-{ echo "keyserver $GPG_KEYSERVER";
-  echo 'keyserver hkps://hkps.pool.sks-keyservers.net';
-  echo 'keyserver-options auto-key-retrieve';
+if [[ "$GPG_KEYSERVER" != 'hkps://hkps.pool.sks-keyservers.net' ]]; then
+    { echo "keyserver $GPG_KEYSERVER";
+      echo 'keyserver hkps://hkps.pool.sks-keyservers.net'; } >> "/home/$ADD_USERNAME/.gnupg/gpg.conf"
+else
+      echo 'keyserver hkps://hkps.pool.sks-keyservers.net' >> "/home/$ADD_USERNAME/.gnupg/gpg.conf"
+fi
+
+{ echo 'keyserver-options auto-key-retrieve';
   echo '';
   echo '# default preferences';
   echo 'personal-digest-preferences SHA256';