remember obfuscation level

src/borg/compress.pyx

@@ -527,6 +527,7 @@ class ObfuscateSize(CompressorBase):
     def __init__(self, level=None, compressor=None, legacy_mode=False):
         super().__init__(level=level, legacy_mode=legacy_mode)  # data will be encrypted, so we can tell the level
         self.compressor = compressor
+        self.level = level
         if level is None:
             pass  # decompression
         elif 1 <= level <= 6:
@@ -568,6 +569,7 @@ class ObfuscateSize(CompressorBase):
         trailer = bytes(addtl_size)
         obfuscated_data = compressed_data + trailer
         meta["csize"] = len(obfuscated_data)  # csize is the overall output size of this "obfuscation compressor"
+        meta["olevel"] = self.level  # remember the obfuscation level, useful for rcompress
         return meta, obfuscated_data  # for borg2 it is enough that we have the payload size in meta["psize"]
 
     def decompress(self, meta, data):