Fixing UnicodeEncodeError against volume creating function

When creating a volume with non-English characters and there is
not enough space for it, then an UnicodeEncodeError occurs. So
we need convert any coded exception message to unicode string
for logging.

Fixes bug 1223128

Change-Id: If1d4faad2bcde696f20565deb01226de33caccad
Turn db model object into a primitive object to avoid error

In volume API controller we need turn db model object into a primitive
object to avoid error when it adding visible administrator metadata to
volume's metadata dict.

Fixes bug: 1220232

Change-Id: I5f6c4fc8dd6ca3af02db577b37dcaeee92bb42e5
Signed-off-by: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Merge "Turn db model object into a primitive object to avoid error"
Merge "Fixing UnicodeEncodeError against volume creating function"