gdb/continuations: remove the 'err' from 'do_all_inferior_continuations'
The 'err' parameter of 'do_all_inferior_continuations' is effectively
unused. There is only one place where the function is called, and
there the argument is a literal 0. So, remove the parameter.
gdb/ChangeLog:
2021-04-22 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>