Fixed the EAP security issue

Fixed the EAP security issue

Description :
1. App send anonymous identity and connect with EAP network.
   And connman store it inside corresponding network pointer.
2. Then if user disconnect that connection,forgetAP will be called.
   And connman does not clear last anonymous identity data for that service.
3. Next time when user again connect with same EAP network, but without anonymous identity.
   Then previous anonymous identity will be passwed to WPA suplicant. But blank anonymous identity should be treated.

Change-Id: I267bea4d394390e82351ae997229c69785ea6d6d
Signed-off-by: Bhaskar Dutta <bhaskar.d@samsung.com>