Do not list qemu binary with -spice in the name

It's create confusion and you can enable spice with the -spice
options.

Fix https://github.com/GNS3/gns3-gui/issues/981

gns3server/modules/qemu/__init__.py

@@ -117,6 +117,8 @@ class Qemu(BaseManager):
         for path in Qemu.paths_list():
             try:
                 for f in os.listdir(path):
+                    if f.endswith("-spice"):
+                        continue
                     if (f.startswith("qemu-system") or f.startswith("qemu-kvm") or f == "qemu" or f == "qemu.exe") and \
                             os.access(os.path.join(path, f), os.X_OK) and \
                             os.path.isfile(os.path.join(path, f)):