Update "rhc cartridge" usage

Author: BanzaiMan

README

@@ -24,7 +24,7 @@ of use.  The following list are some common variables but far from exhaustive:
     os.environ['OPENSHIFT_DATA_DIR']  - For persistent storage (between pushes)
     os.environ['OPENSHIFT_TMP_DIR']   - Temp storage (unmodified files deleted after 10 days)
 
-When embedding a database using 'rhc app cartridge add', you can reference environment
+When embedding a database using 'rhc cartridge add', you can reference environment
 variables for username, host and password:
 
 If you embed MySQL, then:

wsgi/openshift/settings.py

@@ -19,7 +19,7 @@
 
 if ON_OPENSHIFT:
     # os.environ['OPENSHIFT_MYSQL_DB_*'] variables can be used with databases created
-    # with rhc app cartridge add (see /README in this git repo)
+    # with rhc cartridge add (see /README in this git repo)
     DATABASES = {
         'default': {
             'ENGINE': 'django.db.backends.sqlite3',  # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.