rpm: move unified python-sphinx build dependency

Now that the python-sphinx build dependency is unified, move it
to the proper section of the spec file.

Signed-off-by: Nathan Cutler <ncutler@suse.com>
(cherry picked from commit 1d897da)

ceph.spec.in

@@ -108,6 +108,7 @@ BuildRequires:	python
 BuildRequires:	python-devel
 BuildRequires:	python-nose
 BuildRequires:	python-requests
+BuildRequires:	python-sphinx
 BuildRequires:	python-virtualenv
 BuildRequires:	snappy-devel
 BuildRequires:	util-linux
@@ -179,8 +180,6 @@ BuildRequires:	FastCGI-devel
 BuildRequires:	expat-devel
 BuildRequires:	fcgi-devel
 %endif
-# python-sphinx
-BuildRequires:	python-sphinx
 #hardened-cc1
 %if 0%{?fedora} || 0%{?rhel}
 BuildRequires:  redhat-rpm-config