Description : "my_print_defaults" does not mask the
password while printing it.

Analysis : "my_print_defaults" does not mask the password
value before printing while displaying all the config param
values.

Fix : In "my_print_defaults", the password arguments are
masked by default while printing. An new  option,
"--show" has been introduced in this utility which is used
to print passwords without masking.

NOTE : mtr test case not added since '--password' option's
value cannot be specified at the command line.