Remove Salt deprecations and switch tests to Salt 2017.7

Change-Id: If96f95fdab13eae187a843f81b0d0060339a5f98
diff --git a/tests/pillar/system.sls b/tests/pillar/system.sls
index 497aee2..d542587 100644
--- a/tests/pillar/system.sls
+++ b/tests/pillar/system.sls
@@ -61,6 +61,7 @@
       testuser:
         enabled: true
         name: testuser
+        password: passw0rd
         sudo: true
         uid: 9999
         full_name: Test User