client: don't call osutil.HomeDir during test.

Prep for future changing which makes this crash.

Change-Id: Ic02f7319deffb1d47e89f45d066fa4e62d45e499
leak: fix test print

Change-Id: I936cf556bf2e26d4862d6427f790aa4f5fca32f1
leak: disable test by default for now

Change-Id: Idf590dc4b69b69e860c0d321428b18a30bf77254
osutil: fail if used during tests

Disabled by default for now. Will fix cases and set by default, to proactively
catch future testing mistakes.

Change-Id: If292ccd105e214ee888bcad98efb4e49f052e4fd