Allow debug to be disabled by setting PAPI_DEBUG to 0

From: Daniel Drake <d.drake@mmm.com>

Index: papi-0.0.2/setup.py
===================================================================
--- papi-0.0.2.orig/setup.py
+++ papi-0.0.2/setup.py
@@ -43,7 +43,9 @@ def pkg_get_all_cflags (name):
 
 def get_papi_defines ():
     """Builds the defines list for the C Compiler."""
-    val = [("DEBUG", PAPI_DEBUG), ("VERSION", "\"" + PAPI_VERSION + "\"")]
+    val = [("VERSION", "\"" + PAPI_VERSION + "\"")]
+    if PAPI_DEBUG != "0":
+        val.append(("DEBUG", PAPI_DEBUG))
     if sys.platform == "win32":
         val.append (("IS_WIN32", "1"))
     return val