Encrypt widget on update.

Encrypt widget on update.

[Issue#] N/A
[Problem] Widget's content was not encrypted after updating it though
encryption was enabled.
[Cause] Encryption step was not included in the update task.
[Solution] Include encryption in the update task.
[Verification]
1. Build.
2. Install some widget with encryption enabled.
3. Check that widget's start page is encrypted.
4. Install the same widget again. (Update)
5. Check that widget's start page is still encrypted.

Change-Id: I29c13be324a3ab774084ed90fa5ebf59f687433a