Fix for [TCM-3097] - Wifi turns off automatically

Fix for [TCM-3097] - Wifi turns off automatically

Description: The WiFi state was not remembered so when the
application was started again the state was always off in
case of emulator. Also in case of emulator the radio button
was on initially on for a short duration and then turned to
off for every time the application was started.

The solution was to use a vconf key and set/get the key
in case of emulator instead of using wifi-manager calls
as in the case of hardware device. When the application
is launched we get the vconf key value and restore the
state again.

Change-Id: I0a9c3355a80d298864374a122bad69588f1df96a
Signed-off-by: Abhishek Sansanwal <abhishek.s94@samsung.com>