Implementing the feature at BUG#26964 "option --no-beep for mysqladmin".

Option --no-beep is added to mysqladmin like it already exists in
the "mysql" command-line client (short option: -b; long: --no-beep).
Default is to emit beeps like that "mysql" client.
Can't test in the testsuite; but on my Linux I tested by hand:
open a *xterm* and there do "mysqladmin shutdown" - I hear a beep;
with --no-beep, no beep.


client/mysqladmin.cc:
  new option --no-beep like in mysql.cc: if used, no beeps (ASCII 7, BEL)
  are emitted upon errors. Default is to emit beeps, like mysql.cc.