Prevent ourselves from attempting to call an instance method if the import plugin host instance is null here.  Closes #4955.
Prevent ourselves from attempting to call an instance method if the import plugin host instance is null here.  Closes #4955.
jimbonator/shotwell,polymeris/shotwell,Sanva/shotwell-gsoc,h4ck3rm1k3/shotwell,jimbonator/shotwell,abrauchli/shotwell,Sanva/shotwell-gsoc,jimbonator/shotwell,ritchiewilson/shotwell,polymeris/shotwell,abrauchli/shotwell,polymeris/shotwell,damianmoore/shotwell,damianmoore/shotwell,damianmoore/shotwell,abrauchli/shotwell,h4ck3rm1k3/shotwell,h4ck3rm1k3/shotwell,ritchiewilson/shotwell,ritchiewilson/shotwell,Sanva/shotwell-gsoc