xenconfig: fix spice mousemode and copypaste

xenconfig: fix spice mousemode and copypaste

From xl.cfg950 man page:

spiceagent_mouse=BOOLEAN
Whether SPICE agent is used for client mouse mode. The default is
true (1) (turn on)

spicevdagent=BOOLEAN
Enables spice vdagent. The Spice vdagent is an optional component for
enhancing user experience and performing guest-oriented management
tasks. Its features includes: client mouse mode (no need to grab
mouse by client, no mouse lag), automatic adjustment of screen
resolution, copy and paste (text and image) between client and domU.
It also requires vdagent service installed on domU o.s. to work.
The default is 0.

spice_clipboard_sharing=BOOLEAN
Enables Spice clipboard sharing (copy/paste). It requires spicevdagent
enabled. The default is false (0).

So if spiceagent_mouse is enabled (client mouse mode) or
spice_clipboard_sharing is enabled, spicevdagent must be enabled.
Along with this change, s/spicedvagent/spicevdagent, set
spiceagent_mouse correctly, and add a test for these spice
features.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>