use a more common rst header hiearchy

While rst doesn't actually care about the order of headers, reviewers
sometimes do. And the build in emacs mode has a certain order
specified that it can easily rotate between.

Standardize on == h1, = h2, - h3, ~ h4 in the code.

Change-Id: I80ff6df6ef0703a3c3005809069428018bb355d4
diff --git a/doc/source/faq.rst b/doc/source/faq.rst
index b7943ba..f39471c 100644
--- a/doc/source/faq.rst
+++ b/doc/source/faq.rst
@@ -7,7 +7,7 @@
 -  `Miscellaneous <#misc>`__
 
 General Questions
-~~~~~~~~~~~~~~~~~
+=================
 
 Q: Can I use DevStack for production?
     A: No. We mean it. Really. DevStack makes some implementation
@@ -77,7 +77,7 @@
     is valuable so we do it...
 
 Operation and Configuration
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+===========================
 
 Q: Can DevStack handle a multi-node installation?
     A: Indirectly, yes. You run DevStack on each node with the
@@ -157,7 +157,7 @@
     ``FORCE_PREREQ=1`` and the package checks will never be skipped.
 
 Miscellaneous
-~~~~~~~~~~~~~
+=============
 
 Q: ``tools/fixup_stuff.sh`` is broken and shouldn't 'fix' just one version of packages.
     A: [Another not-a-question] No it isn't. Stuff in there is to