Bug#804552: Pandas documentation package is empty

[Rebecca N. Palmer]

Also changing the ipython dependency to ipython3 fixes this.

The documentation so built does contain some error messages in its 
example output (the examples are run during build), including attempts 
to download data (not allowed in Debian package builds), and attempts to 
use modules we don't build-depend on (statsmodels, xarray, 
pyarrow|fastparquet, feather, sqlalchemy, rpy2 - though note that some 
of these would be circular dependencies).

--- a/debian/control
+++ b/debian/control
@@ -52,7 +52,7 @@ Build-Depends: debhelper (>= 9),
                 xauth,
                 xclip,
  Build-Depends-Indep:
- ipython (>= 0.12) | ipython2x | ipython1x,
+ ipython3,
  Build-Conflicts: python-tables (= 3.3.0-4), python3-tables (= 3.3.0-4)
  X-Python-Version: >= 2.7
  X-Python3-Version: >= 3.2
--- a/debian/rules
+++ b/debian/rules
@@ -141,10 +141,7 @@ ifeq (,$(filter nodoc,$(DEB_BUILD_OPTIONS)))
  ifneq (,$(findstring -a,$(DH_INTERNAL_OPTIONS)))
         : # not building documentation in -a
  else
-       : # not building documentation ATM since requires ipython 0.11
-       export PYTHONPATH=`/bin/ls -d 
$$PWD/$(PACKAGE2_ROOT_DIR)/usr/lib/python$(PYVER)/*`; \
-       export MPLCONFIGDIR=$(CURDIR)/build HOME=$(CURDIR)/build; \
-        cd doc; LC_ALL=C python make.py html
+       cd doc && 
PYTHONPATH=$(CURDIR)/$(PACKAGE3_ROOT_DIR)-lib/usr/lib/python3/dist-packages:$(CURDIR)/$(PACKAGE3_ROOT_DIR)/usr/lib/python3/dist-packages 
MPLCONFIGDIR=$(CURDIR)/build HOME=$(CURDIR)/build LC_ALL=C python3 
make.py html
  endif
  endif
         : # Use jquery from Debian package, so prune shipped one