chromium: add exception to testing library list

The depot_tools package used to build Chromium (see
slapos!1014) installs some Python
libraries (NumPy and PIL) with shared objects that don't have RPATH set.
These shouldn't actually be used when running Chromium, but they cause
the testing framework to complain about missing libraries.

slapos/testing/check_software.py

@@ -107,6 +107,10 @@ def checkSoftware(slap, software_url):
       '*/*__compile__/*',
       # build dir for packages built in-place
       '*/parts/wendelin.core/build/*',
+      # the depot_tools package used to build Chromium installs some
+      # Python libraries lacking an rpath; these are not actually used
+      # by Chromium itself
+      '*/.vpython-root/*',
   ))
 
   software_hash = md5digest(software_url)