Update connection/connection.c

according to "man epoll_ctl":
BUGS
       In kernel versions before 2.6.9, the EPOLL_CTL_DEL operation required a non-NULL pointer in event, even though this argument is ignored.  Since kernel  2.6.9,
       event can be specified as NULL when using EPOLL_CTL_DEL.
Merge pull request #10 from lx1988cyk/patch-1

Update connection/connection.c
skynet.blockcall concurrent bugfix
bugfix: blockcall
bugfix: blockcall dispatching
bugfix: connection closed
bugfix: pack table when size == 31
remove duplicate line
Fix bug in connection service

current connection number only increase
Merge pull request #13 from hlouis/master

Fix bug in connection service
Make for Freebsd
client : put unsend bytes into temp buffer
gate support write, and service client forward message to gate
gate readme
bugfix
bugfix
avoid close socket duplicate
bugfix in Mac OSX
bug fix about epoll event cache machanism: socket may be closed by a previous epoll event's processing
Merge pull request #17 from footer/master

bug fix in gate