Restore support for Python3.6 on LTS 18.04 (#1061)

Removed one debug print, and replaced `typing.OrderedDict` with
`typing.Dict` (brings little and breaks compat)

gef.py

@@ -84,7 +84,7 @@
 from io import StringIO, TextIOWrapper
 from types import ModuleType
 from typing import (Any, ByteString, Callable, Dict, Generator, Iterable,
- Iterator, List, NoReturn, Optional, OrderedDict, Sequence, Set, Tuple, Type, TypeVar,
+ Iterator, List, NoReturn, Optional, Sequence, Set, Tuple, Type, TypeVar,
  Union, cast)
 from urllib.request import urlopen
 
@@ -6466,7 +6466,6 @@ def do_invoke(self, _: List[str], **kwargs: Any) -> None:
  return
  try:
  arena_addr = parse_address(args.arena_address)
- print(f"{arena_addr=:#x}")
  arena = GlibcArena(f"*{arena_addr:#x}")
  self.dump_chunks_arena(arena, ctx)
  except gdb.error:
@@ -9678,8 +9677,8 @@ def __init__(self) -> None:
  gef.config["gef.main_arena_offset"] = GefSetting("", str, "Offset from libc base address to main_arena symbol (int or hex). Set to empty string to disable.")
  gef.config["gef.propagate_debug_exception"] = GefSetting(False, bool, "If true, when debug mode is enabled, Python exceptions will be propagated all the way.")
 
- self.commands : OrderedDict[str, GenericCommand] = collections.OrderedDict()
- self.functions : OrderedDict[str, GenericFunction] = collections.OrderedDict()
+ self.commands : Dict[str, GenericCommand] = collections.OrderedDict()
+ self.functions : Dict[str, GenericFunction] = collections.OrderedDict()
  self.missing: Dict[str, Exception] = {}
  return
 
@@ -10121,13 +10120,13 @@ def __init__(self) -> None:
 
  def invoke(self, args: Any, from_tty: bool) -> None:
  self.dont_repeat()
- missing_commands = gef.gdb.missing
+ missing_commands: Dict[str, Exception] = gef.gdb.missing
  if not missing_commands:
  ok("No missing command")
  return
 
- for missing_command, reason in missing_commands.items():
- warn(f"Command `{missing_command}` is missing, reason {RIGHT_ARROW} {reason}")
+ for cmd, reason in missing_commands.items():
+ warn(f"Missing `{cmd}`, reason: {str(reason)}")
  return