Mute partio error prints

[olegul]

Description

This patch mutes the error printed to std::err from inside Partio when it fails to read a pointcloud. OSL's pointcloud_search and pointcloud_find already reports errors "the proper way" via errorfmt, so a failed read will still thrown an error. Plain prints like this can sneak past log-limiting filtering and result in very large log files.

Currently, running something like

shader partioerror(){ float test[1]; if(pointcloud_search("non-existing",P,1.0,1,"test",test)) printf("Success"); }

in testshade, will print

Partio: No extension detected in filename ERROR: pointcloud_search: could not open "non-existing"

with the patch, it will just print ERROR: pointcloud_search: could not open "non-existing"

Tests

I haven't added any tests yet

Checklist:

• [X ] I have read the contribution guidelines.
• [X] I have updated the documentation, if applicable.
• [X ] I have ensured that the change is tested somewhere in the testsuite (adding new test cases if necessary).
• [X ] My code follows the prevailing code style of this project. If I haven't already run clang-format v17 before submitting, I definitely will look at the CI test that runs clang-format and fix anything that it highlights as being nonconforming.

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: olegul (09f449c28f9ae0382bc2877f297e18b3d2802651)

[lgritz]

@olegul You need to click the right things to add yourself to the CI. You're already approved on the SPI end, but you need to accept it.