[gnome-continuous] Disable libusb for GVFS

[Emmanuele Bassi <ebassi src gnome org>]

commit b75ceffd86d2ec9696279c8a989d15fecb94d320
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Nov 30 01:46:18 2017 +0000

    Disable libusb for GVFS
    
    Temporarily, until we bump up the dependency to 1.0.21, as required by
    GVFS.

 manifest.json |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/manifest.json b/manifest.json
index 22dfafc..ca19ad4 100644
--- a/manifest.json
+++ b/manifest.json
@@ -877,6 +877,7 @@
                                  "-Dmtp=false",
                                  "-Dgoogle=false",
                                  "-Dnfs=false",
+                                 "-Dlibusb=false",
                                  "-Ddevel_utils=false",
                                 "-Dinstalled_tests=true"]},