apibuild.py: fix TypeError raised in except clause
apibuild.py: fix TypeError raised in except clause

When an exception happened inside the try clause in serialize_function,
a new exception was raised in the except clause subsequently:

Traceback (most recent call last):
  File "./apibuild.py", line 2529, in <module>
    rebuild("libvirt")
  File "./apibuild.py", line 2513, in rebuild
    builder.serialize()
  File "./apibuild.py", line 2467, in serialize
    self.serialize_function(output, function)
  File "./apibuild.py", line 2208, in serialize_function
    self.warning("Failed to save function %s info: " % name, `id.info`)
TypeError: warning() takes exactly 2 arguments (3 given)

Use the correct number of arguments for self.warning and print the
original exception to stderr.

andreabolognani/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,datto/libvirt,libvirt/libvirt,eskultety/libvirt,jardasgit/libvirt,eskultety/libvirt,datto/libvirt,cbosdo/libvirt,siboulet/libvirt-openvz,agx/libvirt,shugaoye/libvirt,cbosdo/libvirt,olafhering/libvirt,elmarco/libvirt,fabianfreyer/libvirt,libvirt/libvirt,trainstack/libvirt,nertpinx/libvirt,rlaager/libvirt,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,siboulet/libvirt-openvz,VenkatDatta/libvirt,trainstack/libvirt,taget/libvirt,VenkatDatta/libvirt,eskultety/libvirt,agx/libvirt,libvirt/libvirt,datto/libvirt,zhlcindy/libvirt-1.1.4-maintain,VenkatDatta/libvirt,zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,shugaoye/libvirt,trainstack/libvirt,eskultety/libvirt,jardasgit/libvirt,trainstack/libvirt,olafhering/libvirt,shugaoye/libvirt,nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,elmarco/libvirt,andreabolognani/libvirt,olafhering/libvirt,iam-TJ/libvirt,rlaager/libvirt,taget/libvirt,iam-TJ/libvirt,elmarco/libvirt,rlaager/libvirt,nertpinx/libvirt,trainstack/libvirt,iam-TJ/libvirt,elmarco/libvirt,siboulet/libvirt-openvz,cbosdo/libvirt,eskultety/libvirt,iam-TJ/libvirt,jfehlig/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,trainstack/libvirt,taget/libvirt,agx/libvirt,fabianfreyer/libvirt,siboulet/libvirt-openvz,datto/libvirt,taget/libvirt,fabianfreyer/libvirt,iam-TJ/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,taget/libvirt,trainstack/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,crobinso/libvirt,cbosdo/libvirt,datto/libvirt,rlaager/libvirt,jardasgit/libvirt,jardasgit/libvirt,jfehlig/libvirt,zippy2/libvirt,iam-TJ/libvirt,siboulet/libvirt-openvz,zippy2/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,agx/libvirt,agx/libvirt,elmarco/libvirt,andreabolognani/libvirt,jfehlig/libvirt,shugaoye/libvirt,shugaoye/libvirt,zhlcindy/libvirt-1.1.4-maintain,andreabolognani/libvirt,iam-TJ/libvirt,jardasgit/libvirt