classes: Remove references to _remove in function names since this may become a bitba...

classes: Remove references to _remove in function names since this may become a bitbake keyword

There is a good chance we might want to support a bitbake operator
"_remove" which works in a similar way to _append and _prepend. As
such, we can't use those keywords in function or variable names.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Saul Wold <sgw@linux.intel.com>