Update travis.cfg

Un-pin setuptools, add section for Plone 5.x.

travis.cfg

@@ -15,7 +15,6 @@ parts +=
     zptlint
 
 # network speedup
-socket-timeout = 3
 allow-hosts =
     *.plone.org
     *.python.org
@@ -67,6 +66,7 @@ plone.mls.listing = git git://github.com/propertyshelf/plone.mls.listing.git
 
 [versions-4.1.x]
 plone.app.testing = 4.2.2
+setuptools =
 
 # Required by plone.app.dexterity >= 2.0
 z3c.form = 3.0.0a3
@@ -83,6 +83,7 @@ pygments = 1.6
 # 4.2.7 is currently not available as UnifiedInstaller.
 Plone = 4.2.6
 collective.js.jqueryui = 1.8.16.9
+setuptools =
 
 # Keep RF/SL stuff up to date to avoid random failures.
 pygments = 1.6
@@ -92,3 +93,7 @@ pygments = 1.6
 # Keep RF/SL stuff up to date to avoid random failures.
 pygments = 1.6
 plone.app.jquery = 1.8.3
+setuptools =
+
+[versions-5.0.x]
+setuptools =