cfm: No longer keep track of bad remote MPs and MAIDS.

cfm: No longer keep track of bad remote MPs and MAIDS.

Ben pointed out that an attacker could cause OVS to use infinite
memory by sending a series of CCMs with different MAIDs.  Each
message would cause a remote_maid to be allocated and stored for
several seconds.

Since Commit 1c2e2d2fc8 (cfm: Don't report unexpected remote
endpoints) no longer reports unexpected remote MAIDS and MPs in the
database, the only reason to keep track of this information is for
debugging purposes.  In my judgment, it provides negligible useful
debugging information at the expense of significantly increased
code complexity.  This commit rips it out entirely.