Avoid unnecessary Fortran checks

VELOCIraptor doesn't use Fortran, and therefore checking for a Fortran
compiler and runtime libraries is not necessary. Furthermore this can
introduce unnecessary problems; in my case it prevented me to compile
SWIFT with VELOCIraptor in our local platform.

I suspect the appearance of these checks is a remnant from a potential
copy-paste from the grackle integration checks appearing just before
VELOCIraptor's.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

configure.ac

@@ -1244,8 +1244,6 @@ AC_ARG_WITH([velociraptor],
     [with_velociraptor="no"]
 )
 if test "x$with_velociraptor" != "xno"; then
-   AC_PROG_FC
-   AC_FC_LIBRARY_LDFLAGS
    if test "x$with_velociraptor" != "xyes" -a "x$with_velociraptor" != "x"; then
       VELOCIRAPTOR_LIBS="-L$with_velociraptor -lvelociraptor -lmpi -lstdc++ -lhdf5"
       CFLAGS="$CFLAGS -fopenmp"