multilib_script: fix packages split

multilib_script: fix packages split

In multilib_script.bbclass it renames script file which listed in
MULTILIB_SCRIPTS. It may mix up packages split. Take package curl as
example, ${bindir}/curl-config is packaged to curl-dev originally. But
it is renamed to curl-config-${MULTILIB_SUFFIX} and packaged to curl
when multilib is enabled.

And expand 'pkg' to fix QA warning:

| WARNING: Variable key FILES_${PN}-dev (
| ${bindir}/curl-config-${MULTILIB_SUFFIX}) replaces original key
| FILES_curl-dev (${includedir} ${FILES_SOLIBSDEV} ... ${bindir}/*-config)

Insert a necessary space to the argument 'value' of d.appendVar() as well.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>