Fix two coverity issues about uninitialised variables

apps/openmw/mwphysics/physicssystem.cpp

@@ -996,6 +996,7 @@ namespace MWPhysics
         , mWaterCollision(waterCollision)
         , mSkipCollisionDetection(actor.skipCollisions() || !actor.getCollisionMode())
         , mNeedLand(false)
+        , mStuckFrames(0)
     {
     }
 

components/resource/scenemanager.cpp

@@ -237,6 +237,7 @@ namespace Resource
         , mMaxAnisotropy(1)
         , mUnRefImageDataAfterApply(false)
         , mParticleSystemMask(~0u)
+        , mDepthFormat(0)
     {
     }