Makefile.am: fix .gitignore not being generated in spice-protocol/spice
Makefile.am: fix .gitignore not being generated in spice-protocol/spice

By adding spice-protocol to SUBDIRS configure and make will be called in it.

Spotted by Marc-André.

freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,freedesktop-unofficial-mirror/spice__spice-common,elmarco/spice-common,fgouget/spice-common,Fantu/spice-common,SPICE/spice-common,SPICE/spice-common,elmarco/spice-common,fgouget/spice-common,elmarco/spice-common,elmarco/spice-common,SPICE/spice-common,Fantu/spice-common,Fantu/spice-common,freedesktop-unofficial-mirror/spice__spice-common,fgouget/spice-common,freedesktop-unofficial-mirror/spice__spice-common,Fantu/spice-common