Fix "should should" typo

src/stub

             echo ""
             echo "        Note that in case of debian/package.install files,"
             echo "        PREFIX based paths (eg. /usr/bin) in this file should"
-            echo "        should be as if PREFIX was /usr."
+            echo "        be as if PREFIX was /usr."
             echo ""
             echo "        In case of Fedora-based distro, you should make use"
             echo "        of RPM macros:"