Remove redundant code in endpoint.go
Remove redundant code in endpoint.go

- JoinOption, LeaveOption, EndpointOption are all the same thing

Signed-off-by: Alessandro Boch <5bd2eb5b6f60921d9a2b9cb6a0a86bb947f3d361@docker.com>

tangkun75/libnetwork,sharmasushant/libnetwork,msagheer/libnetwork,kunalkushwaha/libnetwork,mountkin/libnetwork,mahak/libnetwork,abronan/libnetwork,mahak/libnetwork,AdoHe/libnetwork,allencloud/libnetwork,AdoHe/libnetwork,docker/libnetwork,coolljt0725/libnetwork,tmakita/libnetwork,anortef/libnetwork,carlye566/libnetwork_eric,jimmycmh/libnetwork,aboch/libnetwork_new,calavera/libnetwork,mbanikazemi/libnetwork,frntn/libnetwork,vdemeester/libnetwork,allencloud/libnetwork,wulonghui/libnetwork,mbanikazemi/libnetwork,chenchun/libnetwork,abhi/libnetwork,sanimej/libnetwork,ycaihua/libnetwork,YujiOshima/libnetwork,vdemeester/libnetwork,abronan/libnetwork,aboch/libnetwork_new,cpuguy83/libnetwork,WeiZhang555/libnetwork,msabansal/libnetwork,sharmasushant/libnetwork,clnperez/libnetwork,junxu/libnetwork,lindenlab/libnetwork,tangkun75/libnetwork,mavenugo/libnetwork,mapuri/libnetwork,hackersdotmu/libnetwork,curtiszimmerman/libnetwork,kvasdopil/libnetwork,runcom/libnetwork,LK4D4/libnetwork,vijayendrabvs/libnetwork,medallia/libnetwork,sanimej/libnetwork,anshulr/libnetwork,YujiOshima/libnetwork,rogaha/libnetwork,fcrisciani/libnetwork,jvinod/libnetwork,tgraf/libnetwork,LK4D4/libnetwork,axsh/libnetwork,Microsoft/libnetwork,tgraf/libnetwork,jimmycmh/libnetwork,kolyshkin/libnetwork,tmakita/libnetwork,thockin/libnetwork,kolyshkin/libnetwork,cpuguy83/libnetwork,wcwxyz/libnetwork,coolljt0725/libnetwork,mahak/libnetwork,argvader/libnetwork,mavenugo/libnetwork,kvasdopil/libnetwork,djones-skytap/libnetwork,vijayendrabvs/libnetwork,mYmNeo/libnetwork,frntn/libnetwork,kunalkushwaha/libnetwork,hw-qiaolei/libnetwork,msabansal/libnetwork,ityangchen/libnetwork,pyakpyak/libnetwork,wulonghui/libnetwork,mapuri/libnetwork,amitkris/libnetwork,sainath14/libnetwork,mountkin/libnetwork,brewertribe/libnetwork,abhi/libnetwork,medallia/libnetwork,pyakpyak/libnetwork,anarcher/libnetwork,djones-skytap/libnetwork,brahmaroutu/libnetwork,minhoryang/libnetwork,vdemeester/libnetwork,WeiZhang555/libnetwork,minhoryang/libnetwork,wcwxyz/libnetwork,rogaha/libnetwork,bprashanth/libnetwork,lindenlab/libnetwork,brahmaroutu/libnetwork,calavera/libnetwork,cloudflare/libnetwork,anarcher/libnetwork,carlye566/libnetwork,curtiszimmerman/libnetwork,dcbw/libnetwork,ityangchen/libnetwork,brewertribe/libnetwork,anshulr/libnetwork,Microsoft/libnetwork,squaremo/libnetwork,abhi/libnetwork,sainath14/libnetwork,carlye566/libnetwork,jmzwcn/libnetwork,amitkris/libnetwork,clnperez/libnetwork,junxu/libnetwork,argvader/libnetwork,hw-qiaolei/libnetwork,mYmNeo/libnetwork,boucher/libnetwork,anortef/libnetwork,chenchun/libnetwork,boucher/libnetwork,thockin/libnetwork,carlye566/libnetwork_eric,axsh/libnetwork,cloudflare/libnetwork,runcom/libnetwork,msagheer/libnetwork,jmzwcn/libnetwork,dcbw/libnetwork,jvinod/libnetwork,squaremo/libnetwork,ycaihua/libnetwork,hackersdotmu/libnetwork,docker/libnetwork,bprashanth/libnetwork,medallia/libnetwork,fcrisciani/libnetwork,docker/libnetwork,kolyshkin/libnetwork