fix: Wrong .dll name for Windows

Author: gcarreno

src/leveldb.common.pas

@@ -53,7 +53,7 @@   leveldb_writeoptions_t = record end;
   libname = 'libleveldb.so';
 {$ENDIF}
 {$IFDEF WINDOWS}
-  libname = 'libleveldb.dll'; // May have a different name
+  libname = 'leveldb.dll'; // May have a different name
 {$ENDIF}
 {$IFDEF DARWIN}
   libname = 'libleveldb.dylib'; // May have a different name