Bug 1032119 - Fix sdcard tests

These tests were failing for multiple reasons.  The semiauto harness was hardcoded to pass a version of "1.3" to fxos_appgen, which in turn had incorrect permissions for sdcard access.

I've already patched fxos_appgen.  This PR allows us to pass a --version parameter to semiauto and have it used to generate the test app.  It also re-enables the sdcard tests, and they all pass with this patch on a 2.0 Flame.