Remove dependency on ConverterMapping name in pylint (oppia#7631)

* Fix an issue with configparser import failures for some Python distributions.

* Fix pylint-quotes

scripts/install_prerequisites.sh

@@ -34,4 +34,9 @@ sudo apt-get install python-dev
 sudo apt-get install python-pip
 sudo apt-get install unzip
 sudo apt-get install python-yaml
+# This is only done to address an
+#     "ImportError: No module named functools_lru_cache"
+# error. See the Troubleshooting page for details:
+#    https://github.com/oppia/oppia/wiki/Troubleshooting
+sudo apt-get install python-matplotlib
 sudo pip install --upgrade pip

scripts/install_third_party_libs.py

@@ -229,7 +229,7 @@ def main(args=None):
     pip_dependencies = [
         ('pylint', '1.9.4', common.OPPIA_TOOLS_DIR),
         ('Pillow', '6.0.0', common.OPPIA_TOOLS_DIR),
-        ('pylint-quotes', '0.1.8', common.OPPIA_TOOLS_DIR),
+        ('pylint-quotes', '0.2.1', common.OPPIA_TOOLS_DIR),
         ('webtest', '2.0.33', common.OPPIA_TOOLS_DIR),
         ('isort', '4.3.20', common.OPPIA_TOOLS_DIR),
         ('pycodestyle', '2.5.0', common.OPPIA_TOOLS_DIR),
@@ -242,6 +242,23 @@ def main(args=None):
     for package, version, path in pip_dependencies:
         ensure_pip_library_is_installed(package, version, path)
 
+    # Do a little surgery on configparser in pylint-1.9.4 to remove dependency
+    # on ConverterMapping, which is not implemented in some Python
+    # distributions.
+    configparser_filepath = os.path.join(
+        common.OPPIA_TOOLS_DIR, 'pylint-1.9.4', 'configparser.py')
+    newlines = []
+    with python_utils.open_file(configparser_filepath, 'r') as f:
+        for line in f.readlines():
+            if line.strip() == 'ConverterMapping,':
+                continue
+            if line.strip().endswith('"ConverterMapping",'):
+                newlines.append(line[:line.find('"ConverterMapping"')] + '\n')
+            else:
+                newlines.append(line)
+    with python_utils.open_file(configparser_filepath, 'w+') as f:
+        f.writelines(newlines)
+
     # Download and install required JS and zip files.
     python_utils.PRINT('Installing third-party JS libraries and zip files.')
     install_third_party.main(args=[])

scripts/pre_commit_linter.py

@@ -571,7 +571,7 @@
     os.path.join(_PARENT_DIR, 'oppia_tools', 'browsermob-proxy-0.8.0'),
     os.path.join(_PARENT_DIR, 'oppia_tools', 'esprima-4.0.1'),
     os.path.join(_PARENT_DIR, 'oppia_tools', 'pycodestyle-2.5.0'),
-    os.path.join(_PARENT_DIR, 'oppia_tools', 'pylint-quotes-0.1.8'),
+    os.path.join(_PARENT_DIR, 'oppia_tools', 'pylint-quotes-0.2.1'),
     os.path.join(_PARENT_DIR, 'oppia_tools', 'selenium-3.13.0'),
     os.path.join(_PARENT_DIR, 'oppia_tools', 'PyGithub-1.43.7'),
     os.path.join(_PARENT_DIR, 'oppia_tools', 'Pillow-6.0.0'),