nativeloader: Ignore empty java_permitted_path

Passing empty permitted path should result in no-op.
This addresses review comment on CL with commit
f334cbf0e1425633bef96a21b0ce9e30f4c6ffa9

Bug: http://b/28639227
Change-Id: I4a4540e522e90a145a374939921932c86f35e88d
(cherry picked from commit d0b1531929d76411d964d4077d441d751e2c01fb)
1 file changed