Retry mount() if it fails with EINTR

mount() may fail EINTR, and when it does this causes dalvik to crash.
Use the regular retry macro to avoid these problems.

Change-Id: I436fe4f0fab36c8172b43b8b9caedcb6d8167a4f
Revert "Finish fixing Zygote descriptor leakage problem"

This reverts commit 9377ea3d2a8a51ae3ce42859e9941109a3dd0eab.