Prepend contentDigest to tmp traceSVG img name (#2644)
Prepend contentDigest to tmp traceSVG img name (#2644)

Fixes #2634
mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,danielfarrell/gatsby,Khaledgarbaya/gatsby,0x80/gatsby,Khaledgarbaya/gatsby,gatsbyjs/gatsby,fabrictech/gatsby,fabrictech/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,0x80/gatsby,0x80/gatsby,Khaledgarbaya/gatsby,danielfarrell/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,danielfarrell/gatsby,fk/gatsby,gatsbyjs/gatsby,fk/gatsby,mingaldrichgan/gatsby,fabrictech/gatsby,fk/gatsby