Convert host value from unicode to a string.

The memcached API expects string format, not unicode.
Convert the host value to a string before creating
the cache_key and passing it to memcached.

Fixes: bug #1158958
Change-Id: I26e86b7fb61b4b3380a14686bd2faa9f58017999
(cherry picked from commit a11c41b48dff83a91eaa65630cc6aeb0e51e6461)
Correct disk's over committed size computing error

There's a error in the disk's over committed size computing for the
instance which using RAW type disk. This issue caused
disk_available_least resource counting increasing.

Fixes bug: 1167695

Change-Id: I4e6cf22a9cf66a757e3641e2a0be0b7699cae69d
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
(cherry picked from commit 32e455282250efa385984085f1ecd8847cc6be2c)
Merge "Correct disk's over committed size computing error" into stable/grizzly
Merge "Convert host value from unicode to a string." into stable/grizzly