tolerate more mime types for cc part of user-data.

Some cloud environments pass multipart user-data as text/x-shellscript.
(I have observed this from old heat on OTC.)
We need to make sure that it is accepted by cloud-init as user-data.
Note that more intelligent logic might pass it correctly as text/x-yaml
which cloud-init should tolerate as well.

Signed-off-by: Kurt Garloff <scs@garloff.de>

cloudinit/user_data.py

@@ -30,7 +30,7 @@
 CONTENT_TYPE = 'Content-Type'
 
 # Various special content types that cause special actions
-TYPE_NEEDED = ["text/plain", "text/x-not-multipart"]
+TYPE_NEEDED = ["text/plain", "text/x-not-multipart", "text/x-shellscript", "text/x-yaml"]
 INCLUDE_TYPES = ['text/x-include-url', 'text/x-include-once-url']
 ARCHIVE_TYPES = ["text/cloud-config-archive"]
 UNDEF_TYPE = "text/plain"