Remove misleading doc for defining user by rascontrol

[Bang Pham Huu]

In ​http://doc.rasdaman.org/02_inst-guide.html#define-new-user, it says

define user u [-passwd p] [-rights r]

u
login name, must be unique (i.e., not yet existing)

-passwd p
set login password to pass (default: user name)
-rights r
rights associated with this login (default: R, i.e., read-only)

But, without specifying -passwd and -rights parameters, e.g:

rasc> define user u1

This user u1 cannot open RASDATA with this rasql query

rasql -q 'select avg_cells(c) from test_mr as c' --user u1 --passwd u1
Opening database RASBASE at localhost:7001... rasdaman error 0: Failed opening DB session

The default text for -passwd and -rights should be removed.