[SECURITY] Fedora 26 Update: qpdf-6.0.0-6.fc26

QPDF is a command-line program that does structural, content-preserving transformations on PDF files. It could have been called something like pdf-to-pdf. It includes support for merging and splitting PDFs and to manipulate the list of pages in a PDF file. It is not a PDF viewer or a program capable of converting PDF into other formats.