ie options: Remove setting OCIO path for test environment

The path is pointing to a deprecated config that doesn't reflect
our current color pipeline or CI/testing environment
anymore.

It created additional issues when running the `IECoreMaya` tests
because autodesk's color management prints exception and error strings
during the test run if the file path is invalid

Author: yannci

config/ie/options

@@ -432,9 +432,6 @@ if targetApp=="rv" :
 # find doxygen
 DOXYGEN = os.path.join( "/software/apps/doxygen", os.environ["DOXYGEN_VERSION"], platform, "bin", "doxygen" )
 
-# we need this so IECoreImage tests use a standard color conversion config
-os.environ["OCIO"] = "/software/config/openColorIO/nuke-default/config.ocio"
-
 # import vars we need to get our doxygen and python wrappers working
 envVarsToImport = [
 	"PATH",