ubifs-utils: common: fix memory leak in devtable.c

ubifs-utils: common: fix memory leak in devtable.c

Report of the static analyzer:
Dynamic memory, referenced by 'line', is allocated at devtable.c:356
by calling function 'getline' and lost at devtable.c:388.
(line: while (getline(&line, &len, f) != -1) {)

Correct explained:
Now line is freed in any exit scenario via out_close which eliminates this error.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.co
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>