gnupg-for-java: purge dead passphrase code

In GnuPG 2.x, gpg-agent handles launching pinentry for getting the
passphrase from the user, so there is no use for Java/JNI code for doing it
since it can't be set up that way anymore.

refs #1585
when running cmd line tests via `adb shell`, check for success

adb shell seems to always return a successful value, even if the script it
ran does not.  Therefore, a little hack is required to get the return value
from the scripts.

refs #1270