Upgrade to animal-sniffer-maven-plugin 1.11

During local builds I experienced something that might have been
http://jira.codehaus.org/browse/MANIMALSNIFFER-8, which is fixed in
newer builds.

Newer animal-sniffer releases also have some performance improvements.
The animal-sniffer:check task now takes roughly a quarter of a
second less time as before on my machine.