Add a string for upload file button.
Add a string for upload file button.

Necessary for http://b/issue?id=2178786.  The rest of the work has
not yet been done, but I am adding the string so it can be
translated.

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base