iotests/197: Fix for non-qcow2 formats

While 197 is very much a qcow2 test, and it looks like the partial
cluster case at the end (introduced in b0ddcbbb) is specifically
a qcow2 case, the whole test scripts actually marks itself to work with
generic formats (and generic protocols, even).

Said partial cluster case happened to work with non-qcow2 formats as
well (mostly by accident), but 18555362 broke that, because it sets
the compat option, which does not work for non-qcow2 formats.

So go the whole way and force IMGFMT=qcow2 and IMGPROTO=file, as done in
other places in this test.

Fixes: 18555362
       ("iotests/197: Fix for compat=0.10")
Reported-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Message-Id: <20200728131134.902519-1-mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

tests/qemu-iotests/197

@@ -114,9 +114,11 @@ echo
 
 # Force compat=1.1, because writing zeroes on a v2 image without a
 # backing file would just result in an unallocated cluster
-_make_test_img -o compat=1.1 1024
-$QEMU_IO -f $IMGFMT -C -c 'read 0 1024' "$TEST_IMG" | _filter_qemu_io
-$QEMU_IO -f $IMGFMT -c map "$TEST_IMG"
+# (Also, note that this is really a pure qcow2 test.)
+IMGPROTO=file IMGFMT=qcow2 TEST_IMG_FILE="$TEST_WRAP" \
+    _make_test_img --no-opts -o compat=1.1 1024
+$QEMU_IO -f qcow2 -C -c 'read 0 1024' "$TEST_WRAP" | _filter_qemu_io
+$QEMU_IO -f qcow2 -c map "$TEST_WRAP"
 _check_test_img
 
 # success, all done

tests/qemu-iotests/197.out

@@ -26,7 +26,7 @@ Images are identical.
 
 === Partial final cluster ===
 
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024
+Formatting 'TEST_DIR/t.wrap.IMGFMT', fmt=IMGFMT size=1024
 read 1024/1024 bytes at offset 0
 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 1 KiB (0x400) bytes     allocated at offset 0 bytes (0x0)