[freebsd91p7][vim] two alias to start CoVim server/client.

vicoserv: 'COVIM_PORT=xxx vicoserv' to start a CoVim server
vicoclnt: 'COVIM_HOST=hhh COVIM_PORT=xxx vicoclnt' to connect to CoVim server
[freebsd91p7][vim] fix alias of CoVim server/client; incorrect expanding variables.