Renamed clean as doclean in Makefile for manuals.

This will prevent `make clean` in unpacked archive from removing
aria2c.1. We don't want to remove them by `make clean` because to
generate aria2c.1, user has to install Sphinx. That is why we
distribute aria2c.1 in the archive.

doc/manual-src/en/Makefile.am

@@ -20,7 +20,7 @@ $(man_MANS): aria2c.rst
 
 # Autogenerated rules by sphinx-quickstart
 
-.PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
+.PHONY: help docclean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
 
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
@@ -41,7 +41,7 @@ help:
 	@echo "  linkcheck  to check all external links for integrity"
 	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
 
-clean:
+docclean:
 	-rm -rf $(BUILDDIR)/*
 
 html:

doc/manual-src/ru/Makefile.am

@@ -21,7 +21,7 @@ $(man_MANS): aria2c.rst
 
 # Autogenerated rules by sphinx-quickstart
 
-.PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
+.PHONY: help docclean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
 
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
@@ -42,7 +42,7 @@ help:
 	@echo "  linkcheck  to check all external links for integrity"
 	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
 
-clean:
+docclean:
 	-rm -rf $(BUILDDIR)/*
 
 html: