Rename VIR_DOMAIN_PAUSED_GUEST_PANICKED to VIR_DOMAIN_PAUSED_CRASHED

Rename VIR_DOMAIN_PAUSED_GUEST_PANICKED to VIR_DOMAIN_PAUSED_CRASHED

The VIR_DOMAIN_PAUSED_GUEST_PANICKED constant is badly named,
leaking the QEMU event name. Elsewhere in the API we use
'CRASHED' rather than 'PANICKED', and the addition of 'GUEST'
is redundant since all events are guest related.

Thus rename it to VIR_DOMAIN_PAUSED_CRASHED, which matches
with VIR_DOMAIN_RUNNING_CRASHED and VIR_DOMAIN_EVENT_CRASHED.

It was added in commit 14e7e0ae8db9843aea80245a3d9e6cf5f2ef720d
which post-dates v1.1.0, so is safe to rename before 1.1.1

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>