Don't download Oracle/Vertica JDBC drivers unless testing them [ci drivers]

bin/ci

@@ -6,12 +6,15 @@ set -eu
 node-0() {
     is_enabled "drivers" && export ENGINES="h2,mongo,mysql,bigquery" || export ENGINES="h2"
     if is_engine_enabled "mongo"; then
-        run_step install-mongodb;
+        run_step install-mongodb
     fi
     run_step lein-test
 }
 node-1() {
     is_enabled "drivers" && export ENGINES="h2,sqlserver,oracle" || export ENGINES="h2"
+    if is_engine_enabled "oracle"; then
+        run_step install-oracle
+    fi
     MB_DB_TYPE=postgres MB_DB_DBNAME=circle_test MB_DB_PORT=5432 MB_DB_USER=ubuntu MB_DB_HOST=localhost \
         run_step lein-test
 }
@@ -73,7 +76,12 @@ install-mongodb() {
     sudo service mongod restart
 }
 
+install-oracle() {
+    wget --output-document=plugins/ojdbc7.jar $ORACLE_JDBC_JAR
+}
+
 install-vertica() {
+    wget --output-document=plugins/vertica-jdbc-7.1.2-0.jar $VERTICA_JDBC_JAR
     docker run --detach --publish 5433:5433 sumitchawla/vertica
     sleep 60
 }

circle.yml

@@ -4,8 +4,6 @@ machine:
   java:
     version:
       oraclejdk8
-  python:
-    version: 2.7.3
   node:
     version: 4.4.7
   services:
@@ -13,19 +11,17 @@ machine:
 dependencies:
   override:
     - lein deps
-    - pip install awscli==1.7.3
     - npm install -g 'yarn@>=0.16.0'
     # Forces the Sauce Connect binary to be downloaded during dependencies phase so it's cached
     - SAUCE_CONNECT_DOWNLOAD_ON_INSTALL=true yarn
     - mkdir plugins
-    - wget --output-document=plugins/ojdbc7.jar $ORACLE_JDBC_JAR
-    - wget --output-document=plugins/vertica-jdbc-7.1.2-0.jar $VERTICA_JDBC_JAR
   cache_directories:
     - "~/.yarn"
     - "~/.yarn-cache"
 database:
   post:
     # MySQL doesn't load named timezone information automatically, you have to run this command to load it
+    # TODO - we only really need to do this step if we're testing against MySQL
     - mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u ubuntu mysql
 test:
   override: