Using nspluginwrapper to run plugins ends up meaning that it needs
unconfined_execmem_exec_t (... and it might mean that we can drop it from
firefox in the future).

avc: denied { execmem } for comm=npviewer.bin egid=500 euid=500
exe=/usr/lib/nspluginwrapper/npviewer.bin exit=-13 fsgid=500 fsuid=500 gid=500
items=0 pid=10729 scontext=system_u:system_r:unconfined_t:s0 sgid=500
subj=system_u:system_r:unconfined_t:s0 suid=500 tclass=process
tcontext=system_u:system_r:unconfined_t:s0 tty=(none) uid=500