OpenEXR 1.x build fix -- include file directory issues.

OpenEXR 2.x uses #include "foo.h", which is the right thing to do.  But
in some places OpenEXR 1.x had #include <foo.h>, which will search only
things in the include path and won't search the same directory as the
enclosing .h file.

Conflicts:
	src/cmake/externalpackages.cmake