btrfs-progs: tests: fix path of btrfs-corrupt-block

There are two utilities that are required for the testsuite but not
installed on systems. The path in tests must be INTERNAL_BIN.

Fix this issue for below tests:
 * fsck-tests/013-extent-tree-rebuild
 * fsck-tests/037-freespacetree-repair
 * misc-tests/038-backup-root-corruption

Issue: #198
Signed-off-by: Long An <lan@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

tests/fsck-tests/013-extent-tree-rebuild/test.sh

@@ -30,7 +30,7 @@ test_extent_tree_rebuild()
 	fi
 
 	# corrupt extent root node block
-	run_check $SUDO_HELPER "$TOP/btrfs-corrupt-block" -l "$extent_root_bytenr" \
+	run_check $SUDO_HELPER "$INTERNAL_BIN/btrfs-corrupt-block" -l "$extent_root_bytenr" \
 		-b 4096 "$TEST_DEV"
 
 	$SUDO_HELPER "$TOP/btrfs" check "$TEST_DEV" >& /dev/null && \

tests/fsck-tests/037-freespacetree-repair/test.sh

@@ -46,7 +46,7 @@ corrupt_fst_item()
 		_fail "Unknown item type for corruption"
 	fi
 
-	run_check "$TOP/btrfs-corrupt-block" -r 10 -K "$objectid,$type,$offset" \
+	run_check "$INTERNAL_BIN/btrfs-corrupt-block" -r 10 -K "$objectid,$type,$offset" \
 		-f offset "$TEST_DEV"
 }
 

tests/misc-tests/038-backup-root-corruption/test.sh

@@ -27,7 +27,7 @@ main_root_ptr=$(dump_super | awk '/^root\t/{print $2}')
 
 [ "$backup2_root_ptr" -eq "$main_root_ptr" ] || _fail "Backup slot 2 is not in use"
 
-run_check "$TOP/btrfs-corrupt-block" -m $main_root_ptr -f generation "$TEST_DEV"
+run_check "$INTERNAL_BIN/btrfs-corrupt-block" -m $main_root_ptr -f generation "$TEST_DEV"
 
 # Should fail because the root is corrupted
 run_mustfail "Unexpected successful mount" \