qemu: properly handle '=' in the VNC socket path
qemu: properly handle '=' in the VNC socket path

If a domain name contains a '=' and the unix socket path is
auto-generated or socket path provided by user contains '=' QEMU
is unable to properly parse the command line.  In order to make it
work we need to use the new command line syntax for VNC if it's
available, otherwise we can use the old syntax.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1352529

Signed-off-by: Pavel Hrdina <d4772d05997b8abf035041e3b4f4996380ea7e7a@redhat.com>

jardasgit/libvirt,fabianfreyer/libvirt,zippy2/libvirt,datto/libvirt,zippy2/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,crobinso/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,datto/libvirt,crobinso/libvirt,zippy2/libvirt,jardasgit/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,nertpinx/libvirt,nertpinx/libvirt,jfehlig/libvirt,libvirt/libvirt,jardasgit/libvirt,jardasgit/libvirt,datto/libvirt,eskultety/libvirt,olafhering/libvirt,datto/libvirt,jardasgit/libvirt,eskultety/libvirt,andreabolognani/libvirt,libvirt/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jfehlig/libvirt,olafhering/libvirt,libvirt/libvirt,crobinso/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,nertpinx/libvirt,olafhering/libvirt,datto/libvirt,olafhering/libvirt,eskultety/libvirt,eskultety/libvirt,nertpinx/libvirt,eskultety/libvirt,zippy2/libvirt