Initialize native library path in PackageSetting

During boot-up we weren't paying attention to the nativeLibraryPath that
was read from the package settings XML file which reset the path to the
default /data/data/<package>/lib directory.

This adds nativeLibraryPath as an argument to the PackageSettings
constructor and related functions that will pull that value in from the
settings file.

It also removes the call to nativeLibraryDir.mkdir() which installd does
by itself.

Change-Id: I53db73c3b1bc90997a4a73f7f2fbaee125e6f67e