BUG/MINOR: contrib/spoa-server: Ensure ip address references are freed

IP addresses references passed in argument for ps_python are not freed after
they have been used. Leading to a small chance of mem leak if a lot of ip
addresses are passed around

This patch must be backported as far as 2.0.
diff --git a/contrib/spoa_server/ps_python.c b/contrib/spoa_server/ps_python.c
index 3ad64a7..427ef18 100644
--- a/contrib/spoa_server/ps_python.c
+++ b/contrib/spoa_server/ps_python.c
@@ -244,6 +244,8 @@
 		PyErr_SetString(spoa_error, "No space left available");
 		return NULL;
 	}
+	/* Once we set the IP value in the worker, we don't need it anymore... */
+	Py_XDECREF(value);
 	return Py_None;
 }
 
@@ -279,6 +281,8 @@
 		PyErr_SetString(spoa_error, "No space left available");
 		return NULL;
 	}
+	/* Once we set the IP value in the worker, we don't need it anymore... */
+	Py_XDECREF(value);
 	return Py_None;
 }