unused variable in ccn-lite-peek

[MahdiBaghbani]

it seems dummy face is doing nothing in ccn-lite-peek:

declared here

https://github.com/cn-uofbasel/ccn-lite/blob/da0d9de8d82349dff845acc62d37242dd09b3d3d/src/ccnl-utils/src/ccn-lite-peek.c#L150

memory space set to all zeros here

https://github.com/cn-uofbasel/ccn-lite/blob/da0d9de8d82349dff845acc62d37242dd09b3d3d/src/ccnl-utils/src/ccn-lite-peek.c#L158

no further usage in code, I guess it was supposed to be removed.