elog-gen.py : order inherited errors

The elog-gen.py script should process errors such that the generated
code has definitions for parent errors before their child errors are
defined.

Change-Id: I035292731346bdba969f549c7e4033066814890f
Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
diff --git a/tools/example/xyz/openbmc_project/Example/Bar.errors.yaml b/tools/example/xyz/openbmc_project/Example/Bar.errors.yaml
new file mode 100644
index 0000000..cff338b
--- /dev/null
+++ b/tools/example/xyz/openbmc_project/Example/Bar.errors.yaml
@@ -0,0 +1,4 @@
+- name: Bar
+  description: this is test error Bar
+  inherits:
+    - Foo