Remove saving prior trap in PROMPT_COMMAND with subshell (#60)
Remove saving prior trap in PROMPT_COMMAND with subshell (#60)

- This was causing crashes in cases where users were doing:
  export PROMPT_COMMAND="history -a; $PROMPT_COMMAND;"

- Original description from contributor:
  $(trap -p DEBUG)" is launching a sub-shell, bash itself. So when people do
  "export PROMPT_COMMAND="history -a; $PROMPT_COMMAND;"", they export form the
  parent shell to subsequent sub-shells. And that creates the infinite loop,
  that eventually segfault bash.
rcaloras/bash-preexec