package/qemu: Bump to version 4.2.0

Other changes:
  - Remove upstream patches
  - Update COPYING.LIB hash as upstream updated the file to match the new LGPL
    2.1 license from upstream. See:
    https://github.com/qemu/qemu/commit/f0d44cc4462f112bce5ec556e87eff4eec682e39



Signed-off-by: Adam Duskett <Aduskett@gmail.com>
Tested-by: Romain Naour <romain.naour@gmail.com>
[Peter: change libssh2 to libssh as pointed out by Vincent Fazio]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>