Fix PR fortran/17237: bug in f-valprint.c

Fix PR fortran/17237: bug in f-valprint.c

This commit fixes the PR mentioned in $subject.  It is about a set but
unused variable that refers to the output format of integer values
printed in Fortran.

This was probably a thinko (like most set-but-unused-vars), but it
could cause an internal error depending on the scenario.  I am sending
a testcase which triggers this error as well.

gdb/ChangeLog:
2014-09-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	PR fortran/17237
	* f-valprint.c (f_val_print): Specify the correct print option to
	use when printing integer values.

gdb/testsuite/ChangeLog:
2014-09-04  Sergio Durigan Junior  <sergiodj@redhat.com>

	PR fortran/17237
	* gdb.fortran/print-formatted.exp: New file.
	* gdb.fortran/print-formatted.f90: Likewise.