[6.0] 03a2102bf assert that -I file processing has finished and closed the fd

[Dridi Boukelmoune]

commit 03a2102bf1237c11586fdf0ce82d5ba9d3c596e0
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Nov 22 10:28:43 2018 +0100

    assert that -I file processing has finished and closed the fd

diff --git a/bin/varnishd/mgt/mgt_main.c b/bin/varnishd/mgt/mgt_main.c
index 237fb0f7f..2e0ee14f5 100644
--- a/bin/varnishd/mgt/mgt_main.c
+++ b/bin/varnishd/mgt/mgt_main.c
@@ -870,6 +870,7 @@ main(int argc, char * const *argv)
 				    "VEV_Once() = %d", o);
 		}
 	}
+	assert(I_fd == -1);
 
 	if (!d_flag && !mgt_has_vcl() && !novcl)
 		MGT_Complain(C_ERR, "No VCL loaded yet");