[SPARK-13887][PYTHON][TRIVIAL][BUILD] Make lint-python script fail fast

## What changes were proposed in this pull request?

Change lint python script to stop on first error rather than building them up so its clearer why we failed (requested by rxin). Also while in the file, remove the commented out code.

## How was this patch tested?

Manually ran lint-python script with & without pep8 errors locally and verified expected results.

Author: Holden Karau <holden@us.ibm.com>

Closes #11898 from holdenk/SPARK-13887-pylint-fast-fail.

dev/lint-python

@@ -60,22 +60,6 @@ export "PYTHONPATH=$SPARK_ROOT_DIR/dev/pylint"
 export "PYLINT_HOME=$PYTHONPATH"
 export "PATH=$PYTHONPATH:$PATH"
 
-# if [ ! -d "$PYLINT_HOME" ]; then
-#     mkdir "$PYLINT_HOME"
-#     # Redirect the annoying pylint installation output.
-#     easy_install -d "$PYLINT_HOME" pylint==1.4.4 &>> "$PYLINT_INSTALL_INFO"
-#     easy_install_status="$?"
-#
-#     if [ "$easy_install_status" -ne 0 ]; then
-#         echo "Unable to install pylint locally in \"$PYTHONPATH\"."
-#         cat "$PYLINT_INSTALL_INFO"
-#         exit "$easy_install_status"
-#     fi
-#
-#     rm "$PYLINT_INSTALL_INFO"
-#
-# fi
-
 # There is no need to write this output to a file
 #+ first, but we do so so that the check status can
 #+ be output before the report, like with the
@@ -92,12 +76,13 @@ fi
 if [ "$lint_status" -ne 0 ]; then
     echo "PEP8 checks failed."
     cat "$PEP8_REPORT_PATH"
+    rm "$PEP8_REPORT_PATH"
+    exit "$lint_status"
 else
     echo "PEP8 checks passed."
+    rm "$PEP8_REPORT_PATH"
 fi
 
-rm "$PEP8_REPORT_PATH"
-
 # Check that the documentation builds acceptably, skip check if sphinx is not installed.
 if hash "$SPHINXBUILD" 2> /dev/null; then
   cd python/docs
@@ -110,29 +95,13 @@ if hash "$SPHINXBUILD" 2> /dev/null; then
     echo "re-running make html to print full warning list"
     make clean
     SPHINXOPTS="-a" make html
+    rm "$SPHINX_REPORT_PATH"
+    exit "$lint_status"
   else
     echo "pydoc checks passed."
+    rm "$SPHINX_REPORT_PATH"
   fi
-  rm "$SPHINX_REPORT_PATH"
   cd ../..
 else
   echo >&2 "The $SPHINXBUILD command was not found. Skipping pydoc checks for now"
 fi
-
-
-# for to_be_checked in "$PATHS_TO_CHECK"
-# do
-#     pylint --rcfile="$SPARK_ROOT_DIR/python/pylintrc" $to_be_checked >> "$PYLINT_REPORT_PATH"
-# done
-
-# if [ "${PIPESTATUS[0]}" -ne 0 ]; then
-#     lint_status=1
-#     echo "Pylint checks failed."
-#     cat "$PYLINT_REPORT_PATH"
-# else
-#     echo "Pylint checks passed."
-# fi
-
-# rm "$PYLINT_REPORT_PATH"
-
-exit "$lint_status"