Filter sun.security.* from smack-java7 Import-Package

Quoting Jens Offenbach:
"The header entry [sun.* in Import-Package] MUST be removed because
its a native package and not exported by the OSGi framework. The bundle
cannot be resolved. It is up to the OSGi framework deployer to declare
this package as beeing "bootdelegated". This tells the classloader of
the bundle to delegate a corresponding package request to the installed
JRE. Only remove this entry and leave the "magic" of resolution to OSGi"

SMACK-343