util: util_dl_close(library) before exiting util_format_s3tc_init.

src/gallium/auxiliary/util/u_format_s3tc.c

@@ -141,6 +141,7 @@ util_format_s3tc_init(void)
       debug_printf("couldn't reference all symbols in " DXTN_LIBNAME
                    ", software DXTn compression/decompression "
                    "unavailable");
+      util_dl_close(library);
       return;
    }
 
@@ -150,6 +151,7 @@ util_format_s3tc_init(void)
    util_format_dxt5_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt5;
    util_format_dxtn_pack = (util_format_dxtn_pack_t)tx_compress_dxtn;
    util_format_s3tc_enabled = TRUE;
+   util_dl_close(library);
 }