Introduce SALT_VERSION var

As we plan to move to salt 2017.7 and at the same time
we need to check 2016.3 as well (and upgrdae path), introduce
new var SALT_VERSION with default value 2016.3

Also update repo path to salt from mirror mirantis and clened up
commented hacks

Reelated: PROD-19373

Change-Id: I3c327aa4b6369750f5bdabe1b96cb52ab5770f03
diff --git a/tcp_tests/templates/cookied-mcp-pike-dvr/_context-environment.yaml b/tcp_tests/templates/cookied-mcp-pike-dvr/_context-environment.yaml
index caec0fa..91208a4 100644
--- a/tcp_tests/templates/cookied-mcp-pike-dvr/_context-environment.yaml
+++ b/tcp_tests/templates/cookied-mcp-pike-dvr/_context-environment.yaml
@@ -210,7 +210,7 @@
       - system.linux.system.repo.mcp.extra
       - system.linux.system.repo.mcp.apt_mirantis.openstack
       - system.linux.system.repo.mcp.apt_mirantis.ubuntu
-      - system.linux.system.repo.mcp.apt_mirantis.saltstack_2016_3
+      - system.linux.system.repo.mcp.apt_mirantis.saltstack
       interfaces:
         ens3:
           role: single_dhcp
@@ -227,7 +227,7 @@
       - system.linux.system.repo.mcp.extra
       - system.linux.system.repo.mcp.apt_mirantis.openstack
       - system.linux.system.repo.mcp.apt_mirantis.ubuntu
-      - system.linux.system.repo.mcp.apt_mirantis.saltstack_2016_3
+      - system.linux.system.repo.mcp.apt_mirantis.saltstack
       interfaces:
         ens3:
           role: single_dhcp