Remove ICC profiles

While checking for copyrighted ICC profiles, under non free license, 
the following file has been spotted, and the ICC profile has been
removed:

      exiftool -icc_profile"-<=" src/skin/menu-other-origins.png

The image has been checked identical to its source, and in addition,
the file is about 3 kB smaller without these useless binary data.

The binary ICC profile itself is “Copyright (c) 1998 Hewlett-Packard
Company” as one can see using `iccdump` once extracted with, e.g.:

      exiftool -icc_profile -b -w icc src/skin/menu-other-origins.png

P.-S.: previously submitted as https://github.com/RequestPolicy/requestpolicy/pull/431 and forwarded by a third party as https://github.com/RequestPolicyContinued/requestpolicy/issues/431 (I didn’t notice it until now).