fix regression in logging runpython errors
fix regression in logging runpython errors

In commit fa044e011d5d7a3525c9b3f2acfe1cbf4a0a96a1 we caught OSError and
started emitting a special error message disclaiming that it probably
isn't Meson's fault, and skipping the generic "This is a meson bug and
should be reported" handler.

But, we no longer did this after verifying that the command *isn't*
runpython, so arbitrary scripts that raised OSError would start saying
stuff about Meson, which was wrong.

Start checking for runpython first.

pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson