cobol: Remove %I spec

cobol: Remove %I spec

Remove %I from the spec string because gcobol does not use the C
preprocessor library and does not search include/ or include-fixed/
directories.  Instead, system copybooks (as they're called) follow the
runtime library and are installed into the LIBSUBDIR, similarly to
Modula-2's .def files.

For compilations relying on non-standard paths (i.e., outside the
installation prefix), -B is already handled by the cobol1 compiler.

gcc/cobol/ChangeLog:

	* gcobol.1: Document -B.
	* lang-specs.h: Remove %I spec.
	* lang.opt: Remove options injected by %I.
	* lang.opt.urls: Likewise.