In zpool_find_import_scan: Reads an uninitialized pointer or
its target Coverity #150966
Found by static analysis with CoverityScan 0.8.5
Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4897