Do not cut off final slash from source path.

Other than somewhat annoying // in path names printed or passed to adb
push/pull, this breaks nothing.

Fixes #9.

adb-sync

@@ -640,7 +640,7 @@ def FixPath(src: bytes, dst: bytes) -> Tuple[bytes, bytes]:
   if pos >= 0:
     if src.endswith(b'/'):
       # Final slash: copy to the destination "as is".
-      src = src[:-1]
+      pass
     else:
       # No final slash: destination name == source name.
       append = src[pos:]