Update the version of keyring to avoid bug

keyring 3.3 generates the following error:
    dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NotSupported:
    Unable to autolaunch a dbus-daemon without a $DISPLAY for X11
The bug is fixed in keyring 3.4

Closes-Bug: #1242992

Change-Id: I2fcb2f67d9d7570d8128f6a37c6930397eaa4a25

global-requirements.txt

@@ -149,7 +149,7 @@ flake8==2.1.0
 hacking>=0.9.2,<0.10
 hgtools # dependency of pytest-runner that is only in setup_requires
 httpretty>=0.8.0,!=0.8.1,!=0.8.2
-keyring>=2.1
+keyring>=2.1,!=3.3
 ldappool>=1.0 # MPL
 mock>=1.0
 mox>=0.5.3