kvm: do not abort if KVM_RUN fails

Just go to the internal error runstate.  This lets you use the "x",
"dump-guest-memory" or "info register" commands.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kvm-all.c

@@ -1738,7 +1738,8 @@ int kvm_cpu_exec(CPUState *cpu)
             }
             fprintf(stderr, "error: kvm run failed %s\n",
                     strerror(-run_ret));
-            abort();
+            ret = -1;
+            break;
         }
 
         trace_kvm_run_exit(cpu->cpu_index, run->exit_reason);