FBR to deploy fedimg==0.7.5

Hi, Submitting a FBR to update the fedimg package to 0.7.5. This update includes a fix[1] to make the snapshot public in the non-us-east-1 region. Earlier, fedimg had an issue where people could copy AMIs to their own account. The last release missed out the case that the snapshots in all the regions should be explicitly made public. [1] https://github.com/fedora-infra/fedimg/pull/60 -- Sayan