Fix issue #9981: rcirc /reconnect command reverts to default port.
rcirc has included a built-in /reconnect command since Emacs 25.1, which
makes the rcirc-reconnect package shipped with the Spacemacs rcirc layer
superfluous.
Modify the rcirc layer's initialization not to load rcirc-reconnect, and
delete rcirc-reconnect from the layer's local packages.