Cannot create new partition with offset 0

[vojtechtrefny]

A partition starting at offset 0 doesn't really make sense, but we currently have a code that should allow it (see udiskslinuxpartitiontable.c#L434). It looks like this no longer works with libblockdev 3.0 (which switched from libparted to libfdisk), see FedoraQt/MediaWriter#644 so this needs to be fixed either here or in libblockdev and a test case should be added to udisks to cover this.