CLOUDSTACK-2568: ACS41 regression in storage subsystem (seen with local storage and 2 or more hosts)

Changes:
- In VolumeReservationVO, the  getter method of a column had a typo, causing us to create a wrong searchbuilder. It was searching over the 'id' column instead of 'vm_reservation_id' causing
- This bug was causing the vm deployment to choose a wrong pool during deployment since the search was choosing incorrectly
- This bug in the GenericSearchBuilder is also fixed - if the getter method does not use the standard 'get' or 'is' prefix, one should annotate that method using
 @Column(name = "<column_name>") and indicate which column this method refers to. This will cause the GenericSearchBuilder to identify the field correctly.