Fix RHEL conditions

0%{?rhel} on Fedora expands to 0 which makes condition 0 < 7 true. You don't want that.

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

SuperLU.spec

@@ -2,7 +2,7 @@
 %global libver 5
 
 ## The RPM macro for the linker flags does not exist on EPEL
-%if 0%{?rhel} < 7
+%if 0%{?rhel} && 0%{?rhel} < 7
 %{!?__global_ldflags: %global __global_ldflags -Wl,-z,relro}
 %endif