Make sure data is sane before dereference

I was seeing a case where data was being passed in as None
and causing an exception.  So to be safe, make sure data
is a value before calling data.strip()

Author: hemna

hwinfo/util/__init__.py

@@ -33,7 +33,10 @@ def __init__(self, data, regexs=None, seperator=None):
         self.set_seperator(seperator)
 
     def set_data(self, data):
-        self.DATA = data.strip()
+        if data:
+            self.DATA = data.strip()
+        else:
+            self.DATA = ""
 
     def set_regexs(self, regexs):
         if regexs: