cygwin docs: patch supervisor with -p2

windows/docs/using-slapos-in-windows.xml

@@ -320,7 +320,7 @@ patch -f --dry-run -p1 < ${_filename} > /dev/null  && patch -p1 &l
 cd $(ls -d /opt/slapos/eggs/supervisor-*.egg/)
 _filename=/opt/git/slapos.package/windows/patches/supervisor-cygwin.patch
 cd supervisor
-patch -f --dry-run -p1 < ${_filename} > /dev/null  && patch -p1 < ${_filename}
+patch -f --dry-run -p2 < ${_filename} > /dev/null  && patch -p2 < ${_filename}
 </programlisting>
 If "slapos node" report "remap error", you need to do as the following,
 <programlisting>