Do not install patched Cython to buildroot

It is not required, and also try hard to not reference buildroot
in cython arguments.

sagemath-rpmbuild.patch

@@ -49,3 +49,15 @@ diff -up src/setup.py.orig src/setup.py
  ### Install also Jupyter kernel spec
  #########################################################
  
+diff -up src/sage/misc/cython.py.orig src/sage/misc/cython.py
+--- src/sage/misc/cython.py.orig	2016-08-24 11:51:48.802265784 -0400
++++ src/sage/misc/cython.py	2016-08-24 11:52:36.723267619 -0400
+@@ -426,7 +426,7 @@ extra_compile_args = %s
+ 
+ ext_modules = [Extension('%s', sources=['%s.%s', %s],
+                      libraries=%s,
+-                     library_dirs=[SAGE_LOCAL + '/lib/'] + %s,
++                     library_dirs=[os.path.realpath(SAGE_LOCAL + '/lib/')] + %s,
+                      extra_compile_args = extra_compile_args,
+                      language = '%s' )]
+ 

sagemath.spec

@@ -872,17 +872,6 @@ ln -sf %{_libdir} $SAGE_LOCAL/lib
 ln -sf %{_includedir} $SAGE_LOCAL/include
 ln -sf %{_datadir} $SAGE_LOCAL/share
 
-#------------------------------------------------------------------------
-%if %{with cython_hack}
-    mkdir -p %{buildroot}%{python_sitearch}
-    cp -far %{python_sitearch}/Cython %{buildroot}%{python_sitearch}
-    PATCH=$PWD/build/pkgs/cython/patches/pxi_sys_path.patch
-    pushd %{buildroot}%{python_sitearch}
-	patch -p1 < $PATCH
-	patch -p1 < %{PATCH27}
-    popd
-%endif
-
 #------------------------------------------------------------------------
 pushd build/pkgs/cysignals/src
     pushd docs
@@ -1195,10 +1184,6 @@ perl -pi -e 's|%{buildroot}||g;' \
 # with docs
 %endif
 
-%if %{with cython_hack}
-    rm -fr %{buildroot}%{python_sitearch}/Cython
-%endif
-
 # Script was used to build documentation
 perl -pi -e 's|%{buildroot}||g;s|^##||g;' %{buildroot}%{_bindir}/sage