This commit fixes a regression introduced by the new $_isvoid convenience

function.  It adds a check for $_isvoid during the test of "show convenience"
output.

gdb/testsuite/
2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/defaults.exp (<show_conv_list>): Add check for $_isvoid
	convenience function.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
+
+	* gdb.base/defaults.exp (<show_conv_list>): Add check for $_isvoid
+	convenience function.
+
 2013-09-17  Pedro Alves  <palves@redhat.com>
 
 	PR gdb/15911

gdb/testsuite/gdb.base/default.exp

@@ -621,6 +621,7 @@ set show_conv_list \
 	{$_probe_arg9 = <error: No frame selected>} \
 	{$_probe_arg10 = <error: No frame selected>} \
 	{$_probe_arg11 = <error: No frame selected>} \
+	{$_isvoid = <internal function _isvoid>} \
     }
 if ![skip_python_tests] {
     append show_conv_list \