[4.0] 57136c2 Disable parallel build due to old sphinx.

[Lasse Karstensen]

commit 57136c2322315ed88e0bacbf6df6759ab8a10287
Author: Lasse Karstensen <lkarsten at varnish-software.com>
Date:   Tue May 13 14:10:41 2014 +0200

    Disable parallel build due to old sphinx.
    
    The sphinx version on git.varnish-cache.org is v1.1.8 which
    hasn't got -j.
    
    In sphinx v1.2.2 (debian jessie) it is in place.
    
    Guess we'll have to live with those extra 820 milliseconds
    per build for now.

diff --git a/doc/sphinx/Makefile.am b/doc/sphinx/Makefile.am
index a5b9718..27f8523 100644
--- a/doc/sphinx/Makefile.am
+++ b/doc/sphinx/Makefile.am
@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line.
 SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build -j4 -W -N -n
+SPHINXBUILD   = sphinx-build -W -N -n
 PAPER         = a4
 BUILDDIR      = build