Fixed some craches in axutil_hash.
Fixed some craches in axutil_hash.

 * Moved calls of the function 'axutil_env_increment_ref' to the
   proper places.
 * Added some checks for allocated memory (compare with NULL).
 * Compare env with ht->env in 'axutil_hash_set_env' function to prevent
   freeing of the env element before assigning if both pointers
   point to the same memory location.

Denisss025/wsfcpp,Denisss025/wsfcpp,Denisss025/wsfcpp,Denisss025/wsfcpp,Denisss025/wsfcpp,Denisss025/wsfcpp,Denisss025/wsfcpp