glx/dri: Initialize reset to __DRI_CTX_RESET_NO_NOTIFICATION.

If the application has requested reset notification, then
dri2_convert_glx_attribs will initialize this to the correct value.

Otherwise, it's supposed to initialize this to NO_NOTIFICATION, but
doesn't when num_attribs == 0.  (The consensus seems to be that we
should make it do so, but that's more invasive, so I'm pushing this for
now.)

Fixes a regression since a8724d85f8
where trying to run OilRush_x86 or apitrace heaven_x64 would result in:

dri_util.c:221: dri2CreateContextAttribs: Assertion `!"Should not get
here."' failed.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=53076
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

src/glx/dri2_glx.c

@@ -241,7 +241,7 @@ dri2_create_context_attribs(struct glx_screen *base,
    uint32_t major_ver = 2;
    uint32_t flags = 0;
    unsigned api;
-   int reset;
+   int reset = __DRI_CTX_RESET_NO_NOTIFICATION;
    uint32_t ctx_attribs[2 * 5];
    unsigned num_ctx_attribs = 0;
 

src/glx/drisw_glx.c

@@ -433,7 +433,7 @@ drisw_create_context_attribs(struct glx_screen *base,
    uint32_t major_ver = 0;
    uint32_t flags = 0;
    unsigned api;
-   int reset;
+   int reset = __DRI_CTX_RESET_NO_NOTIFICATION;
    uint32_t ctx_attribs[2 * 4];
    unsigned num_ctx_attribs = 0;