Bug#804552: Pandas documentation package is empty

[Rebecca N. Palmer]

The build log ( 
https://launchpadlibrarian.net/412630196/buildlog_ubuntu-disco-amd64.pandas_0.23.3-1fakesync1ubuntu3_BUILDING.txt.gz 
) suggests this is due to passing a PYTHONPATH to the just-built 
python-pandas, but not -lib or python3-, causing a failed import.

However, the obvious way to fix this does *not* stop -doc being 
near-empty, so it may not be the only problem.

--- pandas-0.23.3/debian/rules  2018-07-28 05:39:32.000000000 +0100
+++ pandas-0.23.3/debian/rules  2018-07-28 05:39:32.000000000 +0100
@@ -141,10 +141,7 @@
  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