utils: decode command output in runcmd() as UTF-8

Sometimes we get back UTF-8 characters (particularly when picking up
names from git commits), and the ascii codec will error out if that
happens, so switch over to utf-8.

We can as a result remove the decode() calls from the bulk change view.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

layerindex/utils.py

@@ -264,7 +264,7 @@ def runcmd(cmd, destdir=None, printerr=True, logger=None):
     except subprocess.CalledProcessError as e:
         out.seek(0)
         output = out.read()
-        output = output.decode('ascii').strip()
+        output = output.decode('utf-8', errors='replace').strip()
         if printerr:
             if logger:
                 logger.error("%s" % output)
@@ -275,7 +275,7 @@ def runcmd(cmd, destdir=None, printerr=True, logger=None):
 
     out.seek(0)
     output = out.read()
-    output = output.decode('ascii').strip()
+    output = output.decode('utf-8', errors='replace').strip()
     if logger:
         logger.debug("output: %s" % output.rstrip() )
     return output

layerindex/views.py

@@ -224,7 +224,7 @@ def bulk_change_patch_view(request, pk):
     try:
         ret = utils.runcmd('%s bulkchange.py %d %s' % (sys.executable, int(pk), settings.TEMP_BASE_DIR), os.path.dirname(__file__))
         if ret:
-            fn = ret.splitlines()[-1].decode('utf-8')
+            fn = ret.splitlines()[-1]
             if os.path.exists(fn):
                 if fn.endswith('.tar.gz'):
                     mimetype = 'application/x-gzip'
@@ -241,7 +241,6 @@ def bulk_change_patch_view(request, pk):
     except Exception as e:
         output = getattr(e, 'output', None)
         if output:
-            output = output.decode('utf-8', errors="ignore")
             if 'timeout' in output:
                 return HttpResponse('Failed to generate patches: timed out waiting for lock. Please try again shortly.', content_type='text/plain')
             else: