PDFBOX-1888: close ImageInputStream as suggested by Tim Cameron
Task #PDFBOX-1888 - JBIG2Filter is creating an ImageInputStream (with temp file) and not closing it

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/branches/1.8@1565412 13f79535-47bb-0310-9956-ffa450edef68