ofproto-dpif: Actually log errors in facet_check_consistency()

ofproto-dpif: Actually log errors in facet_check_consistency()

facet_check_consistency() goes to some effort to create informative
error messages, protected by a rate limit, but does not actually
log these messages.

This appears to be an unintended side effect of
4dff90977694784e67e9c08cc72dee28ebc343ae ("ofproto-dpif: Move
odp_actions from subfacet to facet.").  This patch restores the
logging behaviour present prior to the above commit.

This patch also reverses a changes made by the same commit to use
ds_put_cstr() instead of ds_put_char() in facet_check_consistency().

Cc: Justin Pettit <jpettit@nicira.com>
Cc: Ethan Jackson <ethan@nicira.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ethan Jackson <ethan@nicira.com>