Thanks a lot Emilio! I appreciate your effort!
I quickly tested this and the import is working now. One minor remark is that some error messages are printed on the command line:
$ geomesa ingest -u root -p password \
> -c myNamespace.countries -f shapeFile TM_WORLD_BORDERS_SIMPL-0.3.shp
May 17, 2017 9:45:11 PM org.geotools.data.shapefile.files.ShpFiles logCurrentLockers
SEVERE: The following locker still has a lock: read on file:/home/dsteiner/Downloads/TM_WORLD_BORDERS_SIMPL-0.3.shp by org.geotools.data.shapefile.shp.ShapefileReader
May 17, 2017 9:45:11 PM org.geotools.data.shapefile.files.ShpFiles logCurrentLockers
SEVERE: The following locker still has a lock: read on file:/home/dsteiner/Downloads/TM_WORLD_BORDERS_SIMPL-0.3.shx by org.geotools.data.shapefile.shp.IndexFile
May 17, 2017 9:45:11 PM org.geotools.data.shapefile.files.ShpFiles logCurrentLockers
SEVERE: The following locker still has a lock: read on file:/home/dsteiner/Downloads/TM_WORLD_BORDERS_SIMPL-0.3.dbf by org.geotools.data.shapefile.dbf.DbaseFileReader