uncrypt: allow reading /proc/bootconfig

It's needed when calling ReadDefaultFstab.

Fixes: 189509028
Test: build
Change-Id: I0d4bac7f2e3a25faa921c8d77cbf92f7808f0ab7
(cherry picked from commit e4116b4e446c79c1f58db3c9b5f331facf9839d9)
1 file changed