Initialize exception value for decide success.

Initialize exception value for decide success.

[Issue#]   N_SE-55213
[Problem]  Sometimes uninstall fail pop up is shown even uninstall is success.
[Cause]    For determining success the exception value was not initialized.
[Solution] Initialize to exception value for decide success.
           In current wrt-installer structure, installer verify this exception value
           at the end of uninstallation. If uninstallation fail, the value is changed
           to error code. If not, this value was initial value.
[Verification] N/A (Not always issue and logical issue)
[SCMRequest] N/A

Change-Id: I8a4bb3bdec871b291fc8d5cd6911bf19720798f5