Move flake8-related packages deps to reqs-dev.txt (apache#5460)

* Move flake8-related packages deps to reqs-dev.txt

My VIM which is integrated with flake8 wouldn't match the output from
travis and would often miss things related to the flake8 plugins
installed using Tox.

By moving this to requirements-dev.txt, we can expect developers would
have the proper configuration locally and get matching results with
Travis when running flake8 or in their IDEs if its integrated with
flake8..

* merging migratinos

* sorting packages

* Specify folder for flake8 processing

* pin pycodestyle==2.3.1

* merge db migrations

requirements-dev.txt

@@ -1,9 +1,16 @@
+console_log==0.2.10
+flake8-coding==1.3.0
+flake8-commas==2.0.0
+flake8-future-import==0.4.5
+flake8-import-order==0.18
+flake8-quotes==1.0.0
+flake8==3.5.0
 flask-cors==3.0.3
 ipdb==0.11
 mysqlclient==1.3.12
-psycopg2==2.7.4
+psycopg2-binary==2.7.5
+pycodestyle==2.3.1
+pylint==1.9.2
 redis==2.10.6
 statsd==3.2.2
 tox==3.1.2
-console_log==0.2.10
-pylint==1.9.2

superset/migrations/versions/46ba6aaaac97_.py

@@ -0,0 +1,22 @@
+"""empty message
+
+Revision ID: 46ba6aaaac97
+Revises: ('705732c70154', 'e3970889f38e')
+Create Date: 2018-07-23 11:20:54.929246
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '46ba6aaaac97'
+down_revision = ('705732c70154', 'e3970889f38e')
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    pass
+
+
+def downgrade():
+    pass

superset/migrations/versions/e3970889f38e_.py

@@ -0,0 +1,22 @@
+"""empty message
+
+Revision ID: e3970889f38e
+Revises: ('4451805bbaa1', '1d9e835a84f9')
+Create Date: 2018-07-22 09:32:36.986561
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'e3970889f38e'
+down_revision = ('4451805bbaa1', '1d9e835a84f9')
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    pass
+
+
+def downgrade():
+    pass

tox.ini

@@ -51,14 +51,9 @@ deps =
 
 [testenv:flake8]
 commands =
-    flake8
+    flake8 {toxinidir}/
 deps =
-    flake8
-    flake8-coding
-    flake8-commas
-    flake8-future-import
-    flake8-import-order
-    flake8-quotes
+    -rrequirements-dev.txt
 
 [testenv:javascript]
 commands =