Bug 906890 - [FTU] Protect against null getDeviceStorage('sdcard')

Change-Id: I159e38415928f2800b728a2ce5822bf6ac45e284
Merge pull request #11619 from mvines/bug906890

Bug 906890 - [FTU] Protect against null getDeviceStorage('sdcard'). r=fcampo
Bug 906753 - [Messages] we should see the recipients count in the header when composing a multi-recipient messag