modules/base: ltn12: source.file() should terminate when an empty chunk is read

The read method of nixio's file and socket objects both return an empty string
when they reach EOF, not nil, causing the consumer to loop endlessly as
source.file() never terminates.

As there is no other situation in which an empty chunk is read, just change it
to nil to terminate the consumer's loop.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Merge pull request #257 from NeoRaider/master

modules/base: ltn12: fix source.file() termination condition
luci.http.protocol: Allow posts to contain more than a single chunk

The ltn12.pump.step() loop in parse_message_body was incorrectly testing
for EOF, and returning after the first chunk, even if further chunks
were available.  The loop in parse_message_header made the correct
check, and test code making raw ajax json posts now succeeds for posts
>= 2048 bytes.

Signed-off-by: Karl Palsson <karlp@remake.is>
Merge pull request #258 from remakeelectric/accept-multi-chunk-post

luci.http.protocol: Allow posts to contain more than a single chunk
Merge pull request #256 from chris5560/master

luci-app-ddns: modified to support ddns-scripts 2.1.0-2