system/vold: check return value of PKCS5_PBKDF2_HMAC_SHA1.

The function PKCS5_PBKDF2_HMAC_SHA1 can fail for a number of reasons and
thus its return value should be checked and handled.

Change-Id: I0f0d8f74b58940a34df16b88434a085760822075
1 file changed