fallback: find_boot_option() needs to return the index for the boot entry in optnum
fallback: find_boot_option() needs to return the index for the boot entry in optnum

The CopyMem() calls in add_to_boot_list() expect that
find_boot_option() returned an index to the matching entry in the
BootOrder array. The previous code returned the numerical portion of
the boot entry label, which in some cases resulted in -1 *
sizeof(CHAR16) being passed to CopyMem() which would in turn corrupt
the running firmware resulting in an exception and a failure to boot
or reset.

rhinstaller/shim,rhinstaller/shim,rhinstaller/shim