dpkg 1.15.8.7: bad interpreter when long tmpdir

dpkg 1.15.8.7: bad interpreter when long tmpdir

When use PACKAGE_CLASSES = "package_deb", and the length of tmpdir is
longer than 177, the error occurs during the image generation:

/very/long/path/totmp/sysroots/x86_64-linux/usr/bin/dpkg-scanpackages:
bad interpreter: No such file or directory

The interpreter is perl, and it does exist, this is because the first
line:

  #!/very/long/path/to/perl

in the script can't be very long.

Create a wrapper for it would fix the problem.

[YOCTO #2640]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>