man: syntax and spelling fixes.
tests: clear inactive table before resuming in teardown
device: if BLKPBSZGET is unavailable, enforce 512

If there is no define for BLKPBSZGET - we have hard time how to
decrypt physical block size - we can't use here block_size,
since this is usually 4k while we need to use 512b.

FIXME: find some better way, until that enforce value 512.
Eventually we could also try to put in:

+#ifndef BLKPBSZGET
+# define BLKPBSZGET _IO(0x12,123)
+#endif

but this will still not work well on old kernels.