EUCA-9093 return client error instead of general error if emi doesn't exist
Merge branch 'testing' into dev/ethomas/EUCA-9093, fixed conflict with clc/modules/cluster-manager/src/main/java/com/eucalyptus/vm/VmControl.java

Conflicts:
	clc/modules/cluster-manager/src/main/java/com/eucalyptus/vm/VmControl.java
Merge branch 'dev/ethomas/EUCA-9093' into testing