Use android_fork_execvp() instead of system(3) to format filesystems

With the recent selinux changes imposed on vold, it no longer has
permission to run a shell, so invoking the filesystem formatting
commands with system(3) gives an error.  So change to using
android_fork_execvp().

Bug: 10279958

Change-Id: Ifa18b28867618858ec7c5cfcc67935e377de38fb
1 file changed