Do not write add / to .deb ar file names.

[aiuto]

Do not write add / to .deb ar file names.
This makes it compatible with dpkg-deb and less incompatible with BSD ar.

• The trailing / is the SysV/GNU ar way to end a name. GNU ar writes name/ padded with spaces. BSD ar writes name padded with spaces and has no terminator. The / lets SysV names contain spaces.
• On macOS, ar is BSD ar, which doesn't know the SysV convention and prints the slash as part of the name. GNU ar tv on Linux should strip it and show debian-binary.
• dpkg tolerates it, but doesn't write it. deb(5) says member names may end in / and dpkg has accepted that since about 1.15.6. dpkg-deb itself writes names with no slash, so our output is not canonical.