Bump version number to 2.1rc1 for release branch
devflow: Bump version to 2.1rc1

Rename package from blktap to blktap-archipelago to resolve
conflicts with the current blktap package that Debian ships.
devflow: Bump version to 2.1rc2
Do not exit on failed info request
Fix compilation error due to incorrect value

Make get_image_info() return EIO on fail.
Wait for xseg I/O handler initialization to complete
Remove useless type casting
Destroy thread attributes object
Free unused memory allocations on close
Bump version