Merge branch 'dd/notes-copy-default-dst-to-head'

"git notes copy $original" ought to copy the notes attached to the
original object to HEAD, but a mistaken tightening to command line
parameter validation made earlier disabled that feature by mistake.

* dd/notes-copy-default-dst-to-head:
  notes: fix minimum number of parameters to "copy" subcommand
  t3301: test diagnose messages for too few/many paramters