storage: Add new events for *PoolBuild() and *PoolDelete().
    
    This commit adds new events for two methods and operations: *PoolBuild() and
    *PoolDelete(). Using the event-test and the commands set below we have the
    following outputs:
    
    $ sudo ./event-test
    Registering event callbacks
    myStoragePoolEventCallback EVENT: Storage pool test Defined 0
    myStoragePoolEventCallback EVENT: Storage pool test Created 0
    myStoragePoolEventCallback EVENT: Storage pool test Started 0
    myStoragePoolEventCallback EVENT: Storage pool test Stopped 0
    myStoragePoolEventCallback EVENT: Storage pool test Deleted 0
    myStoragePoolEventCallback EVENT: Storage pool test Undefined 0
    
    Another terminal:
    $ sudo virsh pool-define test.xml
    Pool test defined from test.xml
    
    $ sudo virsh pool-build test
    Pool test built
    
    $ sudo virsh pool-start test
    Pool test started
    
    $ sudo virsh pool-destroy test
    Pool test destroyed
    
    $ sudo virsh pool-delete test
    Pool test deleted
    
    $ sudo virsh pool-undefine test
    Pool test has been undefined
    
    This commits can be a solution for RHBZ #1475227.
    
    Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1475227
    
    Signed-off-by: Julio Faracco <jcfaracco@gmail.com>
    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>