Fix crash issue of calling disable pkgs from storaged

Fix crash issue of calling disable pkgs from storaged

Currently, storaged calls app2sd api which is synchronous when sdcard
being umounted. Then, app2sd-server calls storage_get_primary_sdcard()
which requests sdcard information to storaged synchronously. This causes
deadlock and storaged gets SIGABRT. However, app2sd-server doesn't need
to call storage_get_primary_sdcard() at current implementaion.

Change-Id: I6a005e6cc7d343929dfbfb8c77264609d457fe23
Signed-off-by: Sangyoon Jang <jeremy.jang@samsung.com>