rgw: If use 'copy part' without 'x-amz-copy-source-range',

rgw: If use 'copy part' without 'x-amz-copy-source-range',

it will copy an entire source object

Signed-off-by: Malcolm Lee <fengxueyu35@126.com>
(cherry picked from commit 753b3a7)

Conflicts:
 1. in original commit, copy_source is std::string, jewel
    version is const char *.
 2. in original commit, url_decode take only one param,
    jewel version take 2 params.
 3. in original commit, get_obj_state take 6 params, jewel
    version takes 4 params.