Support /product partition

This CL will enable reading /product/build.prop and add product paths
into ld.config.txt.in.

Bug: 64195575
Test: tested with 'PRODUCT_PRODUCT_PROPERTIES := ro.product.abc=abc' on
sailfish

Change-Id: Ie996def20e25dc1afe0c74af2096af844934b2dc
5 files changed