Fix vold 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 vold
Change-Id: I1fceba89f1b07228e1677c266f87e431e93f7cb5
1 file changed