[CMSSW_7_0_X] Fix maybe-uninitialized errors in RecoEcal/EgammaClusterAlgos

Fix the following two errors on slc6_amd64_gcc481:
```
RecoEcal/EgammaClusterAlgos/src/PFECALSuperClusterAlgo.cc:276:15: error:
'IsClusteredWithSeed.{anonymous}::IsClustered::phiwidthSuperCluster_'
may be used uninitialized in this function [-Werror=maybe-uninitialized]
   IsClustered IsClusteredWithSeed(seed,_clustype,_useDynamicDPhi);

RecoEcal/EgammaClusterAlgos/src/PFECALSuperClusterAlgo.cc:276:15: error:
'IsClusteredWithSeed.{anonymous}::IsClustered::etawidthSuperCluster_'
may be used uninitialized in this function [-Werror=maybe-uninitialized]

In PFECALSuperClusterAlgo::buildSuperCluster we only check for
PFLayer::ECAL_BARREL and PFLayer::ECAL_ENDCAP. If any other
PFLayer::Layer is returned by seed->the_ptr()->layer()
phiwidthSuperCluster_ and etawidthSuperCluster_ are uninitialized.
```
Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>