rpc: Double buffer size instead of quadrupling buffer size.
rpc: Double buffer size instead of quadrupling buffer size.

When increasing the buffer size up to VIR_NET_MESSAGE_MAX, we
currently quadruple it each time.  This unfortunately means that we
cannot allow certain buffer sizes -- for example the current
VIR_NET_MESSAGE_MAX == 33554432 can never be "hit" since ‘newlen’
jumps from 16MB to 64MB.

Instead of quadrupling, double it each time.

Thanks: Daniel Berrange.
Signed-off-by: Richard W.M. Jones <d9c0c1814229c9d7f78a7e860ff9791c82a22dba@redhat.com>

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