Fix the build (#5403)

The travis build has been failing for 2 reasons recently
* pylint takes > 10 minutes without outputing
* bad merge confict auto resolve in controls.jsx

requirements-dev.txt

@@ -4,5 +4,6 @@ mysqlclient==1.3.12
 psycopg2==2.7.4
 redis==2.10.6
 statsd==3.2.2
-tox==2.9.1
+tox==3.1.2
 console_log==0.2.10
+pylint==1.9.2

superset/assets/src/explore/controls.jsx

@@ -208,7 +208,6 @@ export const controls = {
     multi: true,
     default: [],
     label: t('Percentage Metrics'),
-    default: [],
     validators: [],
     description: t('Metrics for which percentage of total are to be displayed'),
   },

tox.ini

@@ -71,12 +71,10 @@ commands =
 deps =
     -rrequirements.txt
     -rrequirements-dev.txt
-    pylint
 
 [tox]
 envlist =
     eslint
     flake8
     javascript
-    pylint
 skipsdist = true