Bug#815409: no mips for libguestfs, then.

[Hilko Bengen]

control: affects -1 - src:libguestfs

libguestfs as of 1:1.42.4-1 is no longer built on mips, so the source
package is no longer affected by this bug.

If this bug get fixed (or otherwise disappears), I'll happily revert
that change.

Cheers,
-Hilko