Remove sagemath-notebook-export package

This cannot be supported, and is almost certainly broken with python3.
  If anything, should use python2, then could be used on saved notebooks
from when the sagemath package used python1.

sagemath.spec

@@ -59,7 +59,6 @@
 %global polytopes_db_pkg	polytopes_db-20170220
 %global rubiks_pkg		rubiks-20070912
 %global	sagenb_pkg		sagenb-1.1.2
-%global sagenb_export_pkg	sagenb_export-3.2
 %global sagetex_pkg		sagetex-3.2
 %global Sphinx_pkg		Sphinx-1.8.5
 %global singular_pkg		singular-4.1.1p3
@@ -668,16 +667,6 @@ Requires:	python-jupyter-filesystem
 The Sage Notebook is a web-based graphical user interface for
 mathematical software.
 
-#------------------------------------------------------------------------
-%package	notebook-export
-Summary:	The Sage Notebook Exporter
-Requires:	%{name}%{?_isa} = %{version}-%{release}
-Requires:	%{name}-notebook = %{version}-%{release}
-
-%description	notebook-export
-The Sage Notebook Exporter converts SageNB notebooks to other formats,
-in particular IPython/Jupyter notebooks.
-
 #------------------------------------------------------------------------
 %package	rubiks
 Summary:	Several programs for working with Rubik's cubes
@@ -803,11 +792,6 @@ pushd build/pkgs/sagenb
     mv %{sagenb_pkg} src
 popd
 
-pushd build/pkgs/sagenb_export
-    tar zxf ../../../upstream/%{sagenb_export_pkg}.tar.gz
-    mv %{sagenb_export_pkg} src
-popd
-
 pushd build/pkgs/sagetex
     tar zxf ../../../upstream/%{sagetex_pkg}.tar.gz
     mv %{sagetex_pkg} src
@@ -1059,10 +1043,6 @@ pushd build/pkgs/sagenb/src
     %__python3 ./setup.py build
 popd
 
-pushd build/pkgs/sagenb_export/src
-    %__python3 ./setup.py build
-popd
-
 pushd build/pkgs/sagetex/src
     %__python3 ./setup.py build
 popd
@@ -1166,11 +1146,6 @@ pushd build/pkgs/sagenb/src
     ln -sf %{_jsdir}/mathjax %{buildroot}%{python3_sitearch}/sagenb/data/mathjax
 popd
 
-#------------------------------------------------------------------------
-pushd build/pkgs/sagenb_export/src
-    %py3_install
-popd
-
 #------------------------------------------------------------------------
 %if %{with bundled_pexpect}
 pushd build/pkgs/pexpect/src
@@ -1841,13 +1816,6 @@ rm -fr $DOT_SAGE
 %endif
 %{_datadir}/jupyter/kernels/sagemath/
 
-#------------------------------------------------------------------------
-%files		notebook-export
-# GPL+
-%{_bindir}/sagenb-export
-%{python3_sitelib}/sagenb_export
-%{python3_sitelib}/sagenb_export-*.egg-info
-
 #------------------------------------------------------------------------
 %files		rubiks
 # GPL+