PYTHON-1780 Test against Python 2.7 on linux-64-amzn

Author: ShaneHarvey

.evergreen/config.yml

@@ -872,11 +872,12 @@ axes:
   - id: os-fully-featured
     display_name: OS
     values:
-      # https://jira.mongodb.org/browse/BUILD-5453
-      #- id: linux-64-amzn-test
-      #  display_name: "Amazon Linux (Enterprise)"
-      #  run_on: linux-64-amzn-test
-      #  batchtime: 10080  # 7 days
+      - id: linux-64-amzn-test
+        display_name: "Amazon Linux (Enterprise)"
+        run_on: linux-64-amzn-test
+        batchtime: 10080  # 7 days
+        variables:
+           PYTHON_BINARY: "python2.7"
 
       - id: ubuntu-14.04
         display_name: "Ubuntu 14.04"