test: Initializing ChunkReadOp members

test: Initializing ChunkReadOp members

Fixes the coverity issue:
2. uninit_member: Non-static class member offset is not
initialized in this constructor nor in any functions that it calls.
4. uninit_member: Non-static class member length is not
initialized in this constructor nor in any functions that it calls.

CID 1424433 (#1 of 1): Uninitialized scalar field (UNINIT_CTOR)
6. uninit_member: Non-static class member tgt_offset is not initialized
in this constructor nor in any functions that it calls.

Signed-off-by: Amit Kumar amitkuma@redhat.com