Update spice-common submodule

This brings in the following changes:

Frediano Ziglio (1):
      build: Allows to request a greater SPICE protocol version

Signed-off-by: Frediano Ziglio <freddy77@gmail.com>

spice-common @ 402bc6b2

-Subproject commit 47e149705a5bb1d4a615facfd9bd0190d9b0647c
+Subproject commit 402bc6b2371c5e7214c765778f34697fb47cc88e