Remove YAJL include path for Windows builds

YAJL was removed in libbson 1.6.0 (CDRIVER-1370).

Author: jmikola

config.w32

@@ -66,7 +66,6 @@ if (PHP_MONGODB != "no") {
     /I" + configure_module_dirname + "/src/contrib \
     /I" + configure_module_dirname + "/src/libbson/src \
     /I" + configure_module_dirname + "/src/libbson/src/bson \
-    /I" + configure_module_dirname + "/src/libbson/src/yajl \
     /I" + configure_module_dirname + "/src/libmongoc/src/mongoc \
   ";