The threee tags `<name>`, `</name>` and `<command>` were frequently used
with a leading space that this removes. The reason this habbit is so
widespread in testcases is probably that they have been copy and pasted.
Hence, fixing them all now might curb this practice from now on.
Closes#12028
and rename it from 'ftp_list_only' since it is also used for SSH and
POP3. The state is updated internally for 'type=D' FTP URLs.
Added test case 1570 to verify.
Closes#6578