musikr: cleanup

musikr/src/main/jni/shim/iostream_shim.cpp

@@ -116,7 +116,8 @@ namespace taglib_shim
             whence = SEEK_END;
             break;
         default:
-            throw std::runtime_error("Invalid seek position");
+            return;
+            break;
         }
         rust_stream->seek(offset, whence);
     }

musikr/src/main/jni/src/lib.rs

@@ -116,5 +116,7 @@ pub extern "C" fn Java_org_oxycblt_musikr_metadata_MetadataJNI_openFile<'local>(
         None => {}
     }
 
-    jbuilder.build().into_raw()
+
+    let metadata = jbuilder.build();
+    metadata.into_raw()
 }