HTTPCLIENT-1462: include source port, host information in the debug level output

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.3.x@1569329 13f79535-47bb-0310-9956-ffa450edef68
Wire log to include I/O errors and end of stream
FileBodyPart#generateContentType() ignores custom ContentType values