bitbake: data.py: fixes bad substitution when running devshell

bitbake: data.py: fixes bad substitution when running devshell

Running bitbake inside make results in the exported environment variable
MAKEOVERRIDES="${-*-command-variables-*-}", which the shell chokes on
when trying to expand it. But of course, it probably shouldn't have been
trying to expand it in the first place -- so just escape the dollar
sign.

(Bitbake rev: 18cd0ce6a55c9065c3f1bf223b47d817b5efcd8f)

(Bitbake rev: 34226a9e02f319a7547967bbdaca3ca918927dd1)

Signed-off-by: Richard Tollerton <rich.tollerton@ni.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Alejandro Hernandez <alejandro.hernandez@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>