sf: adding pkg-config file

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
properties: adding libandroid-properties pkg-config file

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
Merge pull request #181 from rsalveti/adding-missing-pkg-configs

Adding missing pkg configs for sf and properties.