remove err_no which is not used and creates bug in ReadBlocketteError, change...

remove err_no which is not used and creates bug in ReadBlocketteError, change text in eval to match with new name for read_blkt_xxx

sohstationviewer/model/mseed/blockettes_reader.py

@@ -6,7 +6,7 @@ from struct import unpack
 
 
 class ReadBlocketteError(Exception):
-    def __init__(self, errno, msg):
+    def __init__(self, msg):
         self.msg = msg
 
 
@@ -29,7 +29,7 @@ def read_next_blkt(b_no, data_bytes, byte_order):
 
     try:
         # readBlkt will skip first 4 bytes (HH) as they are already read
-        info = eval("readBlkt%s(%s, %s, '%s')"
+        info = eval("read_blkt_%s(%s, %s, '%s')"
                     % (blockette_type, b_no, data_bytes, byte_order))
     except NameError:
         raise ReadBlocketteError(f"Function to read blockette {blockette_type}"