iotests: make qemu_img_log and img_info_log raise on error

iotests: make qemu_img_log and img_info_log raise on error

Add a `check: bool = True` parameter to both functions and make their
qemu_img() invocations raise on error by default.

users of img_info_log:
206, 207, 210, 211, 212, 213, 237, 242, 266, 274, 302

users of qemu_img_log:
044, 209, 274, 302, 304

iotests 242 and 266 need to use check=False for their negative tests.
iotests 206, 210, 211, 212, 213, 237, 274 and 302 continue working
normally.

As of this commit, all calls to QEMU_IMG made from iotests enforce a
return code of zero by default unless explicitly disabled or suppressed
by passing check=False or with an exception handler.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20220321201618.903471-19-jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>