Explicitly specify encoding when opening text files in Python code

contrib/linearize/linearize-data.py

@@ -75,7 +75,7 @@ def get_blk_dt(blk_hdr):
 # When getting the list of block hashes, undo any byte reversals.
 def get_block_hashes(settings):
     blkindex = []
-    f = open(settings['hashlist'], "r")
+    f = open(settings['hashlist'], "r", encoding="utf8")
     for line in f:
         line = line.rstrip()
         if settings['rev_hash_bytes'] == 'true':
@@ -261,7 +261,7 @@ if __name__ == '__main__':
         print("Usage: linearize-data.py CONFIG-FILE")
         sys.exit(1)
 
-    f = open(sys.argv[1])
+    f = open(sys.argv[1], encoding="utf8")
     for line in f:
         # skip comment lines
         m = re.search('^\s*#', line)