doc: Properly find the version

The conf.py can't import nibabel if nibabel isn't installed, as is the
case when installing nibabel for the first time.

Author: Mathieu Bridon

doc/source/conf.py

@@ -22,8 +22,6 @@
 import sys
 import os
 
-import nibabel
-
 # Check for external Sphinx extensions we depend on
 try:
     import numpydoc
@@ -89,7 +87,7 @@
 # built documents.
 #
 # The short X.Y version.
-version = nibabel.__version__
+version = rel['VERSION']
 # The full version, including alpha/beta/rc tags.
 release = version