Fix installd dump

- Original code of re-opening /proc/self/fd/fd does not work
  due to selinux violation.
- fd (=pipe) passed over binder should be used as it is.

Bug: 202999256
Test: $ adb shell su root dumpsys installd
Change-Id: I4957fb8aa5b17ecec1fae86956a5fcdd93bee57f