local variable 'target_table' referenced before assignment

[mintar]

When running xacro with an incorrectly set scope attribute, a local variable is referenced before assignment.

Steps to reproduce

minimal_example.urdf.xacro:

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
  <xacro:property name="math_pi" value="3.1415926535897931" scope="parent" />
</robot>

$ xacro --inorder minimal_example.urdf.xacro   
math_pi: no parent scope at global scope 
local variable 'target_table' referenced before assignment
UnboundLocalError("local variable 'target_table' referenced before assignment",)
when processing file: minimal_example.urdf.xacro

relevant lines

xacro/src/xacro/__init__.py

Lines 546 to 562 in b786d85

	if scope and scope == 'global':
	target_table = table.root()
	unevaluated = False
	elif scope and scope == 'parent':
	if table.parent:
	target_table = table.parent
	else:
	warning("%s: no parent scope at global scope " % name)
	unevaluated = False
	else:
	target_table = table
	unevaluated = True
	if not unevaluated and isinstance(value, _basestr):
	value = eval_text(value, table)
	target_table._setitem(name, value, unevaluated=unevaluated)

[rhaschke]

@mintar Could you please close this issue if it is solved with #157.