A typo fix in a comment in xlog.c

Hello, I found a duplicate words in the comment of
StartupXLOG@xlog.c and the attached patch fixes it.


Essentially the fix is in one line as follows,

-  * We're in recovery, so unlogged relations relations may be trashed
+  * We're in recovery, so unlogged relations may be trashed

But I did fill-paragraph for the fixed comment so the patch
replaces a little bit more.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

== My e-mail address has been changed since Apr. 1, 2012.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 0c301b2..04dec4e 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6354,10 +6354,10 @@ StartupXLOG(void)        CheckRequiredParameterValues();        /*
-         * We're in recovery, so unlogged relations relations may be trashed
-         * and must be reset.  This should be done BEFORE allowing Hot Standby
-         * connections, so that read-only backends don't try to read whatever
-         * garbage is left over from before.
+         * We're in recovery, so unlogged relations may be trashed and must
+         * be reset.  This should be done BEFORE allowing Hot Standby
+         * connections, so that read-only backends don't try to read
+         * whatever garbage is left over from before.         */
ResetUnloggedRelations(UNLOGGED_RELATION_CLEANUP);