lib: Clean up vlog use.

Vlog functions assume a vlog module has been defined for the current
translation unit.  Including lib/vlog.h from a header file makes the
vlog API visible even when no vlog module may not have been defined.
This patch removes the two cases in the tree where vlog.h was included
from a header file.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
lib/classifier: Add lib/classifier-private.h.

tests/test-classifier.c used to include lib/classifier.c to gain
access to the internal data structures and some utility functions.
This was confusing, so this patch splits the relevant groups of
classifier internal definations to a new file
(lib/classifier-private.h), which is included by both lib/classifier.c
and tests/test-classifier.c.  Other use of the new file is
discouraged.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>