Merge pull request #12093 from julienw/912885-use-innerhtml-instead-of-data-url

Bug 912885 - use innerHTML instead of a data-url to inject attachments i...(cherry picked from commit 9659e823b9461c4ea6baf1477501ac9f202a5ad5)

Conflicts:
	apps/sms/js/attachment.js
Bug 912885 - more tests for bug 912885 r=kaze
(cherry picked from commit d4c347b4a4093c86b3b84df2f0af47e4cb19736c)