Allow writing byte strings with safe_write

Heat files map keeps file contents as byte string in
some cases (i.e. shell scripts). Decode them before
writing to archive.

Closes-Bug: #1915368
Change-Id: I3af14190ebb9d7efbb063299037bd51e38eccd83

tripleoclient/utils.py

@@ -2402,6 +2402,11 @@ def safe_write(path, data):
             path
         )
 
+    try:
+        data = data.decode('utf-8', 'ignore')
+    except (UnicodeDecodeError, AttributeError):
+        pass
+
     try:
         with os.fdopen(os.open(path,
                        os.O_CREAT | os.O_TRUNC | os.O_WRONLY, 0o666),