Address the following warnings reported by PyLint 2.10.2:
************* Module tests-checkds
bin/tests/system/checkds/tests-checkds.py:70:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:120:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/checkds/tests-checkds.py:206:17: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module yamlget
bin/tests/system/digdelv/yamlget.py:22:5: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module stress_http_quota
bin/tests/system/doth/stress_http_quota.py:131:13: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
************* Module tests-rpz-passthru-logging
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:40:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)
bin/tests/system/rpzextra/tests-rpz-passthru-logging.py:44:9: W1514: Using open without explicitly specifying an encoding (unspecified-encoding)