IMPALA-11398: Update flake8 for indent-size=2

Updates flake8 to the latest Python 2-compatible version so we can use
indent-size=2. Our code uses 2-space indents and we have previously
worked around or disabled flake8 checks that rely on 4-space indenting.

Change-Id: Ia701f6e3d86be451ae86d041b799c8a10aee2d93
Reviewed-on: http://gerrit.cloudera.org:8080/18669
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>

infra/python/deps/requirements.txt

@@ -25,10 +25,18 @@ argparse == 1.4.0
 cm-api == 10.0.0
   # Already available as part of python on Linux.
   readline == 6.2.4.1; sys_platform == 'darwin'
-flake8 == 2.6.2
-  mccabe == 0.3.1
-  pycodestyle == 2.0.0
-  pyflakes == 1.2.3
+flake8 == 3.9.2
+  mccabe == 0.6.1
+  pycodestyle == 2.7.0
+  pyflakes == 2.3.1
+  enum34 == 1.1.10
+  typing == 3.10.0.0
+  configparser == 4.0.2
+  functools32 == 3.2.3-2
+  importlib-metadata == 2.1.3
+    contextlib2 == 0.6.0
+    pathlib2 == 2.3.7.post1
+    zipp == 1.2.0
 gcovr == 3.4
 hdfs == 2.0.2
   docopt == 0.6.2
@@ -57,10 +65,10 @@ python-magic == 0.4.11
 pywebhdfs == 0.3.2
   pbr == 3.1.1
 requests == 2.20.0
-   chardet == 3.0.4
-   idna == 2.8
-   urllib3 == 1.24.2
-   certifi == 2020.12.5
+  chardet == 3.0.4
+  idna == 2.8
+  urllib3 == 1.24.2
+  certifi == 2020.12.5
 sasl == 0.2.1
 sh == 1.11
 six == 1.14.0
@@ -72,4 +80,3 @@ avro==1.10.2
 # Required for Kudu:
   Cython == 0.29.14
   pytz == 2020.1
-

setup.cfg

@@ -15,13 +15,14 @@
 # specific language governing permissions and limitations
 # under the License.
 [flake8]
-# E111,E114: These are ignored in order to support 2-space indents.
 # E121,E125,E127,E128: ignored to allow some of the more common idioms for multi-line
 #                      statement indentation used in the Impala code.
 # W503: ignored to allow line breaks before binary operators, as is becoming standard:
 #       https://github.com/python/peps/commit/7690a00d478866
 # E701: ignored to allow if statement body on same line as conditional
 # https://pycodestyle.readthedocs.io/en/latest/intro.html#error-codes
-ignore = E111,E114,E121,E125,E127,E128,W503,E701
+ignore = E121,E125,E127,E128,W503,E701
 # Change from default to conform to Apache Impala line length.
 max-line-length = 90
+# Impala style guide uses 2-space indents.
+indent-size = 2