.gitignore: Adding .idea to .gitignore
.gitignore: Adding .idea to .gitignore

This will keep  all intellij IDEA IDE related files out of git.
This helps contributors using IDEA IDE for development.

lorneli/etcd,bdarnell/etcd,dannysauer/etcd,visheshnp/etcd,ravigadde/etcd,handsomesun/etcd,li-ang/etcd,sebrandon1/etcd,li-ang/etcd,mkumatag/etcd,akauppi/etcd,ajityagaty/etcd,mqliang/etcd,cockroachdb/etcd,CrazyJvm/etcd,rnaveiras/etcd,mickep76/etcd,mkumatag/etcd,jlamillan/etcd,bluebreezecf/etcd,sinsharat/etcd,etcd-io/etcd,a-robinson/etcd,insequent/etcd,cockroachdb/etcd,vimalk78/etcd,bdarnell/etcd,whuwxl/etcd,insequent/etcd,xiang90/etcd,handsomesun/etcd,tguangch/etcd,YuleiXiao/etcd,plasticbox/etcd,plasticbox/etcd,gyuho/etcd,mqliang/etcd,coreos/etcd,etcd-io/etcd,yudai/etcd,mickep76/etcd,yudai/etcd,ravigadde/etcd,fanminshi/etcd,lumjjb/etcd,rnaveiras/etcd,heyitsanthony/etcd,glevand/coreos--etcd,ajityagaty/etcd,vimalk78/etcd,xiang90/etcd,tguangch/etcd,joshix/etcd,ajityagaty/etcd,akauppi/etcd,lorneli/etcd,armstrongli/etcd,CrazyJvm/etcd,armstrongli/etcd,sinsharat/etcd,YuleiXiao/etcd,mqliang/etcd,sebrandon1/etcd,glevand/coreos--etcd,visheshnp/etcd,whuwxl/etcd,bluebreezecf/etcd,mkumatag/etcd,coreos/etcd,joshix/etcd,heyitsanthony/etcd,jlamillan/etcd,gyuho/etcd,lumjjb/etcd,rnaveiras/etcd,etcd-io/etcd,dannysauer/etcd,a-robinson/etcd,fanminshi/etcd