Revert "* use to_irc_netmask(:force => true) to unlink Netmasks from their Server...

Revert "* use to_irc_netmask(:force => true) to unlink Netmasks from their Server to prevent errors when dumping users"

This reverts commit 9a1cf6a11b12c06cd925dd6a789ec98fe750c8ad, since it
was a hack to work around the undumpable Channel (and consequently
Server and Netmask) caused by 847a977b228b35f5ab281a31dd3724a4db887dff
"#any? and #all? methods for Channel#mode to check if modes are set"
and fixed by 8f8205310518e7b0626d657ba9667f7bfc745371 "Dumpable
definition of #any? and #all? methods for Channel#mode"