Skip trying to link to wordpress media if there is no media (#2619)
Skip trying to link to wordpress media if there is no media (#2619)

Resolve https://github.com/gatsbyjs/gatsby/issues/2564
ChristopherBiscardi/gatsby,gatsbyjs/gatsby,Khaledgarbaya/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,Khaledgarbaya/gatsby,gatsbyjs/gatsby,fk/gatsby,fabrictech/gatsby,gatsbyjs/gatsby,danielfarrell/gatsby,Khaledgarbaya/gatsby,danielfarrell/gatsby,gatsbyjs/gatsby,fabrictech/gatsby,ChristopherBiscardi/gatsby,fk/gatsby,0x80/gatsby,0x80/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,fabrictech/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,danielfarrell/gatsby,fk/gatsby