*: Convert some route map functions to return the enum

*: Convert some route map functions to return the enum

Conver these functions:
route_map_add_match
route_map_delete_match
route_map_add_set
route_map_delete_set

To return the `enum rmap_compile_rets` and ensure all functions
that use this code handle all the enumerated possible returns.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>