* doc/gdb.texinfo: Escape "{" and "}".

Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.627
diff -u -r1.627 gdb.texinfo
--- doc/gdb.texinfo	19 Sep 2009 10:46:20 -0000	1.627
+++ doc/gdb.texinfo	21 Sep 2009 07:18:00 -0000
@@ -23361,7 +23361,7 @@
 @smallexample
 (gdb)
 -stack-list-variables --thread 1 --frame 0 --all-values
-^done,variables=[{name="x",value="11"},{name="s",value="{a = 1, b = 2}"}]
+^done,variables=[@{name="x",value="11"@},@{name="s",value="@{a = 1, b = 2@}"@}]
 (gdb)
 @end smallexample