Remove %clean section

None of currently supported distributions need that.
Last one was EL5 which is EOL for a while.

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

perl-Graph.spec

@@ -77,9 +77,6 @@ find $RPM_BUILD_ROOT -type d -depth -exec rmdir {} 2>/dev/null ';'
 make test
 
 
-%clean
-rm -rf $RPM_BUILD_ROOT
-
 
 %files
 %defattr(-,root,root,-)