Fix valgrind warning
Fix valgrind warning

When using the gcin valgrind test, it shows the following messages:

==20624== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ----
==20624== Use of uninitialised value of size 4
==20624==    at 0x5A24DAF: ueStrNCpy (chewing-utf8-util.c:44)
==20624==    by 0x5A1F2A9: InitSymbolTable (chewingutil.c:1415)
==20624==    by 0x4B79DFF: ??? (in /lib/libc-2.14.so)
==20624==
==20624== Use of uninitialised value of size 4
==20624==    at 0x5A24DAF: ueStrNCpy (chewing-utf8-util.c:44)
==20624==    by 0x5A1F508: InitEasySymbolInput (chewingutil.c:1486)
==20624==    by 0x5A1A9F7: chewing_Init (chewingio.c:171)
==20624==    by 0x5A075F6: module_init_win (chewing.cpp:182)
==20624==    by 0x8050B22: init_in_method (eve.cpp:938)
==20624==    by 0x8050601: init_state_chinese (eve.cpp:673)
==20624==    by 0x80506CD: toggle_im_enabled (eve.cpp:726)
==20624==    by 0x8050EE7: ProcessKeyPress (eve.cpp:1128)
==20624==    by 0x807D928: process_client_req (im-dispatch.cpp:288)
==20624==    by 0x807DD82: cb_read_gcin_client_data (im-srv.cpp:41)
==20624==    by 0x49D26CD: ??? (in /usr/lib/libglib-2.0.so.0.2800.8)
==20624==    by 0x498CC4E: g_main_context_dispatch (in
/usr/lib/libglib-2.0.so.0.2800.8)

It seems that there have some uninitialised values in chewingutil.c ,

PeterDaveHello/libchewing,simonfork/libchewing,ShengYenPeng/libchewing,ShengYenPeng/libchewing,school510587/general_index_libchewing,school510587/libchewing-old,mangokingTW/libchewing,ShengYenPeng/libchewing,robert501128/libchewing,PeterDaveHello/libchewing,Seachaos/libchewing,chewing/libchewing,Chocobo1/libchewing,school510587/general_index_libchewing,yan12125/libchewing,robert501128/libchewing,school510587/phlcw130202,Seachaos/libchewing,dimotsai/libchewing,mangokingTW/libchewing,dimotsai/libchewing,kito-cheng/libchewing,bbyykk/libtaigi,PeterDaveHello/libchewing,czchen/libchewing,simonfork/libchewing,PingNote/libchewing,robert501128/libchewing,Seachaos/libchewing,Chocobo1/libchewing,simonfork/libchewing,bbyykk/libtaigi,PeterDaveHello/libchewing,kito-cheng/libchewing,cwlin/libchewing,school510587/libchewing-old,hiunnhue/libchewing,school510587/phlcw130202,school510587/libchewing-phoneless,school510587/libchewing-old,bbyykk/libtaigi,school510587/libchewing-phoneless,school510587/libchewing-phoneless,mangokingTW/libchewing,hiunnhue/libchewing,dimotsai/libchewing,chewing/libchewing,cwlin/libchewing,chewing/libchewing,czchen/libchewing,Chocobo1/libchewing,Chocobo1/libchewing,kito-cheng/libchewing,kito-cheng/libchewing,yan12125/libchewing,Seachaos/libchewing,PingNote/libchewing,ShengYenPeng/libchewing,cwlin/libchewing,Seachaos/libchewing,school510587/phlcw130202,school510587/general_index_libchewing,Chocobo1/libchewing,cwlin/libchewing,cwlin/libchewing,hiunnhue/libchewing,PingNote/libchewing,school510587/libchewing-old,school510587/libchewing-phoneless,chewing/libchewing,yan12125/libchewing,PingNote/libchewing,yan12125/libchewing,czchen/libchewing,bbyykk/libtaigi,dimotsai/libchewing,school510587/phlcw130202,school510587/libchewing-old,hiunnhue/libchewing,simonfork/libchewing,hiunnhue/libchewing,school510587/phlcw130202,mangokingTW/libchewing,school510587/general_index_libchewing,bbyykk/libtaigi,robert501128/libchewing,school510587/libchewing-phoneless,czchen/libchewing