sh: Add test for ${01} and ${010} that already works.

Although it is probably unwise to use this, POSIX is clear that leading
zeroes are permitted in positional parameters (and do not indicate octal).

Such positional parameters are checked for being unset and/or null
correctly, but their value is incorrectly expanded.
Update to bmake-20140620
Main change is detection of malformed variable references.

Reviewed by:	obrien
Merge remote-tracking branch 'upstream/master' into hardened/current/aslr
Merge remote-tracking branch 'origin/hardened/current/aslr' into hardened/current/aslr