nbd patches for 2020-11-16

- silence Coverity false positive
 - modernize iotests python code related to nbd
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Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2020-11-16' into staging

nbd patches for 2020-11-16

- silence Coverity false positive
- modernize iotests python code related to nbd

# gpg: Signature made Mon 16 Nov 2020 20:58:13 GMT
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2020-11-16:
  iotests: Replace deprecated ConfigParser.readfp()
  nbd: Silence Coverity false positive

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

nbd/server.c

@@ -2129,8 +2129,8 @@ static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
     }
 
     if (!full) {
-        /* last non dirty extent */
-        nbd_extent_array_add(es, end - start, 0);
+        /* last non dirty extent, nothing to do if array is now full */
+        (void) nbd_extent_array_add(es, end - start, 0);
     }
 
     bdrv_dirty_bitmap_unlock(bitmap);

tests/qemu-iotests/nbd-fault-injector.py

@@ -227,7 +227,7 @@ def parse_config(config):
 def load_rules(filename):
     config = configparser.RawConfigParser()
     with open(filename, 'rt') as f:
-        config.readfp(f, filename)
+        config.read_file(f, filename)
     return parse_config(config)
 
 def open_socket(path):