vmm: Simplify the vcpu run switch

Use a catchall case for all reasons that we do not handle, and
move the vCPU run switch into its own function.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vmm/src/lib.rs

@@ -4,6 +4,8 @@
 //
 
 extern crate kvm_ioctls;
+#[macro_use]
+extern crate log;
 
 use kvm_ioctls::*;
 use std::fmt::{self, Display};