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-60912

rust-afterburn.spec

@@ -110,6 +110,8 @@ to run in the initramfs on boot.
 %autosetup -n %{crate}-%{version_no_tilde} -p1 %{?rhel:-a1}
 %if 0%{?rhel}
 %cargo_prep -v vendor
+# avoid brp-mangle-shebangs error from sources with executable bit            
+chmod -x vendor/ipnet/src/*.rs
 %else
 %cargo_prep
 %endif