BlockConf: Call backend functions to detect geometry and blocksizes

BlockConf: Call backend functions to detect geometry and blocksizes

geometry: hd_geometry_guess function autodetects the drive geometry.
This patch adds a block backend call, that probes the backing device
geometry. If the inner driver method is implemented and succeeds
(currently only for DASDs), the blkconf_geometry will pass-through
the backing device geometry. Otherwise will fallback to old logic.

blocksize: This patch initializes blocksize properties to 0.
In order to set the property a blkconf_blocksizes was introduced.
If user didn't set physical or logical blocksize, it will
retrieve its value from a driver (only succeeds for DASD), otherwise
it will set default 512 value.

The blkconf_blocksizes call was added to all users of BlkConf.

Signed-off-by: Ekaterina Tumanova <[email protected]>
Reviewed-by: Markus Armbruster <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Message-id: 1424087278[email protected]
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>