Add some constness in log functions

Signed-off-by: Amit Dror <amitd@infinidat.com>
Moved functions for timespec math from ganesha_types.h to common_utils.h

Signed-off-by: Amit Dror <amitd@infinidat.com>
Cast to pool_t* in pool_basic_initializer() return statement

Signed-off-by: Amit Dror <amitd@infinidat.com>