ueventd: restorecon sysfs files

Allow cpufreq governor tuning files to be labelled correctly after
switching governor.

Change-Id: I3e0fd310aaacbb4e647e42597d38040774257955
fs_mgr: add support for "sync" mount flag

Change-Id: I6ad74cfbf98d30320785e3691df30dabc5c54cb9