Fix `make style-check` errors (#1000)

Using flake8 inplace of pyflakes
Renamed run-pyflakes -> run-flake8
Changed target name to flake8 in Makefile

With pyflakes we can't suppress warnings/errors in few required places.
flake8 is flexible in that regard. Hence using flake8 seems to be a
better choice here.

flake8 does the job of pep8 anyway.
So, removed pep8 target from Makefile along with tools/run-pep8 script.

Included setup.py in flake8 checks

1 files changed, 17 insertions, 0 deletions

diff --git a/tools/run-flake8 b/tools/run-flake8
new file mode 100755
index 00000000..0021cdb9
--- /dev/null
+++ b/tools/run-flake8
@@ -0,0 +1,17 @@
+#!/bin/bash
+
+CR="
+"
+pycheck_dirs=( "cloudinit/" "tests/" "tools/"  "setup.py" )
+
+set -f
+if [ $# -eq 0 ]; then
+   files=( "${pycheck_dirs[@]}" )
+else
+   files=( "$@" )
+fi
+
+cmd=( "python3" -m "flake8" "${files[@]}" )
+
+echo "Running: " "${cmd[@]}" 1>&2
+exec "${cmd[@]}"