Re: [Libguestfs] [PATCH] launch: direct: Use old-style file= and format= parameters when not disabling locking (RHBZ#1503497).

Ancient qemu 1.5 (in RHEL 7) does not understand the file.file.filename= and file.driver= parameters. Go back to using the old-style file= and format= parameters when we're not trying to set the file.backing.file.locking=off parameter. Fixes commit 9fe592808ccfd9ed184b88ca9c6cad2e1798dee3. Thanks: Yongkui Guo, Václav Kadlčík. ---