Do not track the isl PDF manual in SVN

There is no point in regularly committing a binary file to the repository, as
this just unnecessarily increases the repository size. Interested people can
find the isl manual for example at isl.gforge.inria.fr/manual.pdf.

llvm-svn: 292105

Author: tobiasgrosser

polly/.gitignore

@@ -1,2 +1,3 @@
 test/lit.site.cfg
+lib/External/isl/doc/manual.pdf
 00*