leveldbwrapper: Remove unused .Prev(), .SeekToLast() methods

Also, trim trailing whitespace.

src/leveldbwrapper.cpp

@@ -149,6 +149,4 @@ std::string CLevelDBWrapper::GetObfuscateKeyHex() const
 CLevelDBIterator::~CLevelDBIterator() { delete piter; }
 bool CLevelDBIterator::Valid() { return piter->Valid(); }
 void CLevelDBIterator::SeekToFirst() { piter->SeekToFirst(); }
-void CLevelDBIterator::SeekToLast() { piter->SeekToLast(); }
 void CLevelDBIterator::Next() { piter->Next(); }
-void CLevelDBIterator::Prev() { piter->Prev(); }

src/leveldbwrapper.h

@@ -88,7 +88,6 @@ public:
     bool Valid();
 
     void SeekToFirst();
-    void SeekToLast();
 
     template<typename K> void Seek(const K& key) {
         CDataStream ssKey(SER_DISK, CLIENT_VERSION);
@@ -99,7 +98,6 @@ public:
     }
 
     void Next();
-    void Prev();
 
     template<typename K> bool GetKey(K& key) {
         leveldb::Slice slKey = piter->key();