Fix build error

Source files should not be executable, to correct this problem we did this fix.
More about: https://github.com/krisprice/ipnet/issues/59

resolves: #https://issues.redhat.com/browse/RHEL-60790

rust-afterburn.spec

@@ -105,6 +105,8 @@ to run in the initramfs on boot.
 %if 0%{?rhel} && !0%{?eln}
 tar xvf %{SOURCE1}
 %cargo_prep -v vendor
+# avoid brp-mangle-shebangs error from sources with executable bit            
+chmod -x vendor/ipnet/src/*.rs
 %else
 %cargo_prep
 %endif