Description of problem:
While trying to isolate a problem, I modified rc.sysinit to print the name of
the module which is being loaded by load_module() and noticed that duplicates
aren't screened out.

Version-Release number of selected component (if applicable):
8.18-1

How reproducible:
Always

Steps to Reproduce:
1. Have load_module() print the name of the module before attempting to load it.
2. Reboot.
  
Actual results:
You may end up getting duplicates (if you have multiple on-board USB
controllers, for example).

Expected results:
Not to see that, maybe a negligibly faster bootup.

Additional info:
(Ab)using $blacklist by adding names of modules to it as we attempt to load it
appears to do the trick:

@@ -197,6 +197,7 @@
        for module in $blacklist ; do
                [ "$1" = "$module" ] && return
        done
+       blacklist="$blacklist $1"
        modprobe $1 >/dev/null 2>&1
 }