Add decode ignore and debugging trace for code update

UnicodeDecodeError:
 'utf-8' codec can't decode byte 0xb5 in position 1: invalid start byte

Changes:
   - Add "ignore" decode directive to leave the character out of
     the Unicode result
   - Add debug tracing for tar image member files.

Change-Id: I1a4648d93dad1f431d68c9e416e645c5aea26c14
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/code_update_utils.py b/lib/code_update_utils.py
index 8490df0..ac1efc9 100644
--- a/lib/code_update_utils.py
+++ b/lib/code_update_utils.py
@@ -9,6 +9,7 @@
 import sys
 import tarfile
 import time
+from robot.libraries.BuiltIn import BuiltIn
 
 robot_pgm_dir_path = os.path.dirname(__file__) + os.sep
 repo_data_path = re.sub('/lib', '/data', robot_pgm_dir_path)
@@ -151,12 +152,15 @@
     version = ""
     tar = tarfile.open(tar_file_path)
     for member in tar.getmembers():
+        BuiltIn().log_to_console(member.name)
+        if member.name != "MANIFEST":
+            continue
         f = tar.extractfile(member)
         content = f.read()
         if content.find(b"version=") == -1:
             # This tar member does not contain the version.
             continue
-        content = content.decode("utf-8").split("\n")
+        content = content.decode("utf-8", "ignore").split("\n")
         content = [x for x in content if "version=" in x]
         version = content[0].split("=")[-1]
         break