Make ibus-config tests side effect free

Make ibus-config tests side effect free

Previously we assumed that test cases are executed in the order of
registration.  This is no longer true after glib change 89aa9dbd which
fixed test case grouping.  Clear the default match rule in each test
case to avoid side effect.

BUG=

Committed: c9ba5e1

[Daiki Ueno, 2013-06-13 02:10:19]

On 2013/06/07 07:05:31, Daiki Ueno wrote:

Without this, ibus-config test fails with glib 2.36 as follows:

$ ./runtest ibus-config
/ibus/create-config-async: OK
/ibus/config-set-get: OK
/ibus/config-watch/default: OK
/ibus/config-watch/section: **
ERROR:ibus-config.c:302:change_and_test: assertion failed (data->section ==
expected_section): ("test/s2" == NULL)

Because the default match rules set by /ibus/create-config-async and
/ibus/config-set-get still remain.  With glib < 2.35, there was no problem since
/ibus/config-watch/* are always called first.

By the way, the following 4 tests are still failing with glib 2.36:

ibus-configservice
ibus-factory
ibus-serializable
ibus-share

Due to a glib bug related to g_type_init() and glib_mem_profier.  
https://bugzilla.gnome.org/show_bug.cgi?id=701694

Perhaps we could eliminate the use of glib_mem_profier in favor of valgrind or
stap?

[Peng, 2013-06-13 12:16:17]

lgtm

[Daiki Ueno, 2013-06-14 02:01:17]

Committed patchset #1 manually as rc9ba5e1 (presubmit successful).