CLI: Fix import of StructureData from QE input file (aiidateam#1018)

The click option already returns a file handle, so the command
itself should not try to open it again, which excepts.

src/aiida_quantumespresso/cli/data/structure.py

@@ -20,8 +20,7 @@ def cmd_import(filename, dry_run):
     """Import a `StructureData` from a Quantum ESPRESSO input file."""
     from aiida_quantumespresso.tools.pwinputparser import PwInputFile
 
-    with open(filename, 'r', encoding='utf-8') as input_file:
-        parser = PwInputFile(input_file.read())
+    parser = PwInputFile(filename.read())
     structure = parser.get_structuredata()
     formula = structure.get_formula()