MINOR: Use new version of ducktape

ducktape diff: https://github.com/confluentinc/ducktape/compare/v0.7.8...v0.7.9

- bcrypt (a dependency of ducktape) dropped Python2.7 support.
ducktape-0.7.9 now pins bcrypt to a Python2.7-supported version.

Author: Andrew Egelhofer <aegelhofer@confluent.io>

Reviewers: Dhruvil Shah <dhruvil@confluent.io>, Manikumar Reddy <manikumar.reddy@gmail.com>

Closes #9192 from andrewegel/trunk

tests/docker/Dockerfile

@@ -33,7 +33,7 @@ LABEL ducker.creator=$ducker_creator
 
 # Update Linux and install necessary utilities.
 RUN apt update && apt install -y sudo netcat iptables rsync unzip wget curl jq coreutils openssh-server net-tools vim python-pip python-dev libffi-dev libssl-dev cmake pkg-config libfuse-dev && apt-get -y clean
-RUN pip install -U pip==9.0.3 setuptools && pip install --upgrade cffi virtualenv pyasn1 boto3 pycrypto pywinrm ipaddress enum34 && pip install --upgrade ducktape==0.7.8
+RUN pip install -U pip==9.0.3 setuptools && pip install --upgrade cffi virtualenv pyasn1 boto3 pycrypto pywinrm ipaddress enum34 && pip install --upgrade ducktape==0.7.9
 
 # Set up ssh
 COPY ./ssh-config /root/.ssh/config

tests/setup.py

@@ -51,7 +51,7 @@ setup(name="kafkatest",
       license="apache2.0",
       packages=find_packages(),
       include_package_data=True,
-      install_requires=["ducktape==0.7.8", "requests==2.22.0"],
+      install_requires=["ducktape==0.7.9", "requests==2.22.0"],
       tests_require=["pytest", "mock"],
       cmdclass={'test': PyTest},
       )