serializer.DumpJson: Control indentation by parameter

If the simplejson module supports indentation, it's always used. There
are cases where we might not want to use it or enable it only for
debugging purposes, such as in RPC.

Reviewed-by: iustinp

lib/serializer.py

@@ -28,6 +28,7 @@ backend (currently json).
 import simplejson
 import re
 
+
 # Check whether the simplejson module supports indentation
 _JSON_INDENT = 2
 try:
@@ -38,14 +39,18 @@ except TypeError:
 _RE_EOLSP = re.compile('[ \t]+$', re.MULTILINE)
 
 
-def DumpJson(data):
+def DumpJson(data, indent=True):
   """Serialize a given object.
 
+  Args:
+  - indent: Whether to indent output (depends on simplejson version)
+
   """
-  if _JSON_INDENT is None:
+  if not indent or _JSON_INDENT is None:
     txt = simplejson.dumps(data)
   else:
     txt = simplejson.dumps(data, indent=_JSON_INDENT)
+
   txt = _RE_EOLSP.sub("", txt)
   if not txt.endswith('\n'):
     txt += '\n'