Remove python-docutils from RPM requirements

This is not in __pkginfo__ nor in debian/control and I could not find any
reference to this in the code.

cubicweb-squareui.spec

@@ -22,7 +22,6 @@
 BuildRequires:  %{python} %{python}-setuptools
 Requires:       cubicweb >= 3.17.2
 Requires:       cubicweb-bootstrap >= 0.5.2
-Requires:       python-docutils
 
 %description
 squareui component for the CubicWeb framework