fix (#268)

fixing issue 264 (incorrect size check when re-opening a storage file for truncation)

storage/storage/src/main/java/org/eclipse/store/storage/types/StorageFile.java

@@ -361,7 +361,7 @@ public final synchronized long copyFrom(
 			}
 		}
 
-		public final synchronized void truncate(final long newLength)
+		public synchronized void truncate(final long newLength)
 		{
 			this.ensureWritable().truncate(newLength);
 		}

storage/storage/src/main/java/org/eclipse/store/storage/types/StorageLiveDataFile.java

@@ -153,6 +153,15 @@ public long totalLength()
 			return this.fileTotalLength;
 		}
 
+		@Override
+		public synchronized void truncate(long newLength)
+		{
+			//Do not use this.internalOpenWriting() because this method does an size check
+			//if the file is re-opened.
+			//This size check is not appropriate if the file shall be opened with write access for truncation.
+			super.internalOpenWriting();
+			super.truncate(newLength);
+		}
 
 		final TypeInFile typeInFile(final StorageEntityType.Default type)
 		{
@@ -287,7 +296,7 @@ protected synchronized boolean internalOpenWriting()
 
 			return true;
 		}
-
+		
 		@Override
 		public final double dataFillRatio()
 		{