DO NOT MERGE Fix the order of loading OEM properties

Move the OEM property imports so that they take higher precedence over
product and can still be overridden by factory properties.

Bug: 171304788
Test: manual

Merged-In: I31f0a582a5c1c55a42fb213c8269b7829aa27b52
Change-Id: I6e17440714e3e5b3a94ec6e1d2f166080513e1a0