Add API Docs for lib/spack/llnl (#3982)

* Add API Docs for lib/spack/llnl
* Clean up after previous builds
* Better fix for purging API docs

lib/spack/docs/Makefile

@@ -9,7 +9,7 @@ PAPER         =
 BUILDDIR      = _build
 
 export PYTHONPATH := ../../spack:$(PYTHONPATH)
-APIDOC_FILES  = spack*.rst
+APIDOC_FILES  = spack*.rst llnl*.rst
 
 # Internal variables.
 PAPEROPT_a4     = -D latex_paper_size=a4
@@ -58,7 +58,8 @@ upload:
 	git push -f github gh-pages
 
 apidoc:
-	sphinx-apidoc -T -o . $(PYTHONPATH)/spack
+	sphinx-apidoc -f -T -o . ../spack
+	sphinx-apidoc -f -T -o . ../llnl
 
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
@@ -83,7 +84,7 @@ help:
 	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
 
 clean:
-	-rm -f package_list.rst command_index.rst modules.rst
+	-rm -f package_list.rst command_index.rst
 	-rm -rf $(BUILDDIR)/* $(APIDOC_FILES)
 
 html: