osdep: Rename qemu_{get, set}_version() to qemu_{, set_}hw_version()

This makes the purpose of the function clearer: it is not about the
version of QEMU that's running, but the version string exposed in the
emulated hardware.

Cc: Andrzej Zaborowski <balrogg@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: John Snow <jsnow@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <1446233769-7892-3-git-send-email-ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
