ZTS: Don't include zpool_create.shlib in zpool_add

The zpool_add tests include zpool_create.shlib for a few silly
variables.

Don't use those variables for the file names. Include zpool_add.kshlib
for whatever variables we still need.

Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #9997

tests/zfs-tests/tests/functional/cli_root/zpool_add/add-o_ashift.ksh

@@ -25,7 +25,7 @@
 #
 
 . $STF_SUITE/include/libtest.shlib
-. $STF_SUITE/tests/functional/cli_root/zpool_create/zpool_create.shlib
+. $STF_SUITE/tests/functional/cli_root/zpool_add/zpool_add.kshlib
 
 #
 # DESCRIPTION:
@@ -49,8 +49,8 @@ function cleanup
 log_assert "zpool add -o ashift=<n>' works with different ashift values"
 log_onexit cleanup
 
-disk1=$TEST_BASE_DIR/$FILEDISK0
-disk2=$TEST_BASE_DIR/$FILEDISK1
+disk1=$TEST_BASE_DIR/disk1
+disk2=$TEST_BASE_DIR/disk2
 log_must mkfile $SIZE $disk1
 log_must mkfile $SIZE $disk2
 

tests/zfs-tests/tests/functional/cli_root/zpool_add/add_nested_replacing_spare.ksh

@@ -25,7 +25,6 @@
 #
 
 . $STF_SUITE/include/libtest.shlib
-. $STF_SUITE/tests/functional/cli_root/zpool_create/zpool_create.shlib
 
 #
 # DESCRIPTION:

tests/zfs-tests/tests/functional/cli_root/zpool_add/add_prop_ashift.ksh

@@ -50,8 +50,8 @@ function cleanup
 log_assert "'zpool add' uses the ashift pool property value as default."
 log_onexit cleanup
 
-disk1=$TEST_BASE_DIR/$FILEDISK0
-disk2=$TEST_BASE_DIR/$FILEDISK1
+disk1=$TEST_BASE_DIR/disk1
+disk2=$TEST_BASE_DIR/disk2
 log_must mkfile $SIZE $disk1
 log_must mkfile $SIZE $disk2