ref-manual: Updated warning regarding libexecdir

Fixes [YOCTO #6398]

Fixed the text according to Ross such that the specified
package contains files in /usr/libexec when the distro
configuration uses a different path for <libexecdir>.
By default libexecdir is $prefix/libexec but this can
be changed, for example to ${libdir}.

(From yocto-docs rev: 6ffe6728994c615abe2689a63f9f055425d08d7e)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-qa-checks.xml

@@ -81,11 +81,13 @@ can be found then it should be implemented.  I can't find one at the moment.
 
                 <para>
                     The specified package contains files in
-                    <filename>/usr/libexec</filename>.
-                    By default, <filename>libexecdir</filename> is set to
-                    "${libdir}/${BPN}" rather than to "/usr/libexec".
-                    Thus, installing to <filename>/usr/libexec</filename>
-                    is likely not desirable.
+                    <filename>/usr/libexec</filename> when the distro
+                    configuration uses a different path for
+                    <filename>&lt;libexecdir&gt;</filename>
+                    By default, <filename>&lt;libexecdir&gt;</filename> is
+                    <filename>$prefix/libexec</filename>.
+                    However, this default can be changed (e.g.
+                    <filename>${libdir}</filename>).
                 </para>
 
                 <para>