AI 145373: remove a debugging printf that sometimes breaks the build

# $(3): list of directories to search for java files in

define prepare-doc-source-list

$(hide) mkdir -p $(dir $(1))

$(hide) echo $(2)

$(call dump-words-to-file, $(2), $(1))

$(hide) for d in $(3) ; do find $$d -name '*.java' >> $(1) 2> /dev/null ; done ; true

endef