WiFi : Fix to DHCP to static IP configuration problem

WiFiStateMachine shall update the IP address configuration to
the kernel through NetworkManagementService.This notification
from the kernel is again sent to the connectivity service
through the NetLinkStateTracker and WiFiStateMachine.
Thus ,if the interface is down during this IP address
reconfiguration (for the case of DHCP to Static IP configuration),
Connectivity service shall be notified with old IP address ,NULL(0)
IP address(signifying interface down) and the latest IP address.
This notification was done by updating the IP address using a local
variable , and hence the second notification on the interface down
is over ridden by the last notification , resulting in missed
interface down notification to the connectivity service.This
resulted in failed data connection when IP address is changed from
DHCP to IP on the fly.
Hence ,this gerrit enhances the design and also pass the updated
IP address to the connectivity service.

Change-Id: I50cd0502c5f8259b1325ed68de870b592d96ae22
CRs-Fixed: 750277
Wifi: Add a flag to indicate duplicate network

Add a flag to indicate if a wifiConfiguration is duplicate or not
This flag decides whether the previous network history along
with IP and proxy configurations are required to be copied
or not.

Change-Id: I663d985031c82e64f889044441daee70d17e5ddc
CRs-Fixed: 760505
Revert "wlan: Provide runtime option to enable or disable rssi threshold (base)"

This reverts commit b95c030a6ffa22b8c96d5358ee34ed835085a172.

RSSI threshold parameters are now user configurable.Below are the
parameters.
THRESHOLD_UNBLACKLIST_HARD_5G
THRESHOLD_UNBLACKLIST_SOFT_5G
THRESHOLD_UNBLACKLIST_HARD_24G
THRESHOLD_UNBLACKLIST_SOFT_24G
THRESHOLD_INITIAL_AUTO_JOIN_ATTEMPT_RSSI_MIN_5G
THRESHOLD_INITIAL_AUTO_JOIN_ATTEMPT_RSSI_MIN_24G

Hence reverting the gerrit

Change-Id: I0d589cd494a488a4618434314e76fefde1275abd
CRs-Fixed: 757958