test: replace calls to individual detach functions with one call to main detach
    
    The individual qemuDomainDetach*Device() functions will soon be "less
    functional", since some of the code that is duplicated in 10 of the 12
    detach functions is going to be moved into the common
    qemuDomainDetachDeviceLive(), which calls them all.
    
    qemuhotplugtest.c is the only place any of these individual functions
    is called other than qemuDomainDetachDeviceLive() itself. Fortunately,
    qemuDomainDetachDeviceLive() provides exactly the functionality needed
    by the test driver (except that it supports detach of more device
    types than the test driver has tests for).
    
    This patch replaces the calls to
    qemuDomainDetach(Chr|Shmen|Watchdog|Disk)Device with a single call to
    the higher level function, allowing us to shift functionality between
    the lower level functions without breaking the tests.
    
    Signed-off-by: Laine Stump <laine@laine.org>
    ACKed-by: Peter Krempa <pkrempa@redhat.com>