ofp-actions: Fix the check for instruction ordering and duplication.

ofp-actions: Fix the check for instruction ordering and duplication.

Open vSwitch enforces that, when instructions appear as Nicira extensions
in OpenFlow 1.0 action lists, the instructions appear in the order that
an OpenFlow 1.1+ switch would execute them and that no duplicates appear.
But the check wasn't general enough, because it had been implemented when
only one instruction was implemented and never later generalized.  This
commit fixes the problem.

One of the tests was actually testing for the wrong behavior that the
check implemented, so this commit corrects that test.  It also updates
another test with updated log messages.

Reported-by: Jing Ai <ai_jing2000@hotmail.com>
Tested-by: Jing Ai <ai_jing2000@hotmail.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>