MINOR: cli: refactor CLI wait command parser

MINOR: cli: refactor CLI wait command parser

Reorganize cli_parse_wait() which is responsible to parse CLI wait
command invocation.

This patch splits the function in two parts. First, args[2] is compared
as string to check the comparison argument and assigned <ctx.cond>
member. The second part of the function reuses <ctx.cond> to perform the
necessary initialization.

This patch will allow to extend wait command to add similar conditions
to the already existing one, without having to either duplicate the code
or perform multiple string comparison.