[PATCH] Clarify semantics of restore_command exit status

Hi,

the documentation is not clear about which of the non-zero exit codes of
a restore_command are considered FATAL and which are considered a
temporary failure.  I had to look at the source to find the answer.
Proposed fix below.

regards,
Andreas

diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index 9092cf8..6fa7d40 100644
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -1114,9 +1114,9 @@ restore_command = 'cp /mnt/server/archivedir/%f %p'
     present in the archive; it must return nonzero when so asked.  This is not
     an error condition.  An exception is that if the command was terminated by
     a signal (other than <systemitem>SIGTERM</systemitem>, which is used as
-    part of a database server shutdown) or an error by the shell (such as
-    command not found), then recovery will abort and the server will not start
-    up.
+    part of a database server shutdown) or an exit status greater than 125
+    (such as command not found by the shell), then recovery will abort and the
+    server will not start up.
    </para>

    <para>
diff --git a/doc/src/sgml/recovery-config.sgml b/doc/src/sgml/recovery-config.sgml
index 26af221..66d5e62 100644
--- a/doc/src/sgml/recovery-config.sgml
+++ b/doc/src/sgml/recovery-config.sgml
@@ -73,8 +73,9 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
 </programlisting>
         An exception is that if the command was terminated by a signal (other
         than <systemitem>SIGTERM</systemitem>, which is used as part of a
-        database server shutdown) or an error by the shell (such as command
-        not found), then recovery will abort and the server will not start up.
+        database server shutdown) or an exit status greater than 125 (such as
+        command not found by the shell), then recovery will abort and the
+        server will not start up.
        </para>
       </listitem>
      </varlistentry>