contacts: don't assume the device has an sdcard

Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

Conflicts:
	src/com/android/contacts/common/MoreContactUtils.java
	src/com/android/contacts/common/vcard/ImportVCardActivity.java

Change-Id: I5c8abfd53527f4ea83e6202c953affd589810774