Added Idea config files to gitignore

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.2.x@1486893 13f79535-47bb-0310-9956-ffa450edef68
HTTPCLIENT-1357: Connection upgrade operation does not resolve default port (-1) to a scheme default value which can lead to a InvalidArgumentException on some platforms

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.2.x@1486894 13f79535-47bb-0310-9956-ffa450edef68