Revert "[FieldService] Target API_14 which we install by default (rather than API_15 which we don't)"

This reverts commit 258c9926aff7a01b4d5b05fb8e12e9d0e455434c.
Revert "Revert "[FieldService] Target API_14 which we install by default (rather than API_15 which we don't)""

This reverts commit 1f1d9fb0552954e877a68bf39a68b5988cd85323.