Add 3 functions to utils_memory for getting some usage info of hugepages.

get_num_anon_huge_pages(pid) : get the anonhugepages' usage amount of a progress
get_num_huge_pages_free() : get the number of free hugepages
get_num_huge_pages_rsvd() : get the number of rsvd hugepages
When I wrote the code. I tried a good way to figure out the actual number of anonymous hugepages that guest used. I don't think the number in /proc/meminfo is a actual number.
To know the way to figure out the actual number of anonymous hugepages that a process used , you can read the doc from kernel.
At first time get_num_huge_pages_rsvd() was wrote through grep to get the number. You don't agree with this thought. So I change to use this way. function read_from_meminfo() get the numbers through grep. Is this a good idea?