[folks] docs: Use the correct Vala version string for valadoc

[Travis Reitter <treitter src gnome org>]

commit 5d4005fb91fafa82d9e7e4c721453e8f5ba820ef
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Fri Jul 5 15:02:47 2013 -0700

    docs: Use the correct Vala version string for valadoc
    
    It was failing to find the expected driver, previously, which broke the
    build

 docs/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/Makefile.am b/docs/Makefile.am
index 364280f..88907ff 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -52,7 +52,7 @@ valadoc_flags = \
        --force \
        --package-version $(PACKAGE_VERSION) \
        --no-protected \
-       --driver "$(shell valac --version)" \
+       --driver "$(shell valac --api-version)" \
        $(NULL)
 
 # folks documentation