Fix ?csearch max timestamp default value.

Fix ?csearch max timestamp default value.

src/opserv.c (opserv_cdiscrim_create): Fix default value for max_ts.
    (With an expression only a coder could love.  Improvements wanted.)
git-archimport-id: srvx@srvx.net--2006/srvx--devo--1.3--patch-21