Set all testing environment variables.

Also add link to Testing wiki page.

Author: AlekSi

.travis.yml

@@ -13,9 +13,12 @@ go:
 
 env:
   global:
+    # See https://github.com/go-sql-driver/mysql/wiki/Testing
     - MYSQL_TEST_USER=gotest
     - MYSQL_TEST_PASS=secret
+    - MYSQL_TEST_PROT=tcp
     - MYSQL_TEST_ADDR=127.0.0.1:3307
+    - MYSQL_TEST_DBNAME=gotest
     - MYSQL_TEST_CONCURRENT=1
 
   # https://www.mysql.com/support/supportedplatforms/database.html