config include: fix leak on relative include path
config include: fix leak on relative include path

Found through static analysis

SirCmpwn/sway,taiyu-len/sway,ascent12/sway,1ace/sway,ascent12/sway,taiyu-len/sway,taiyu-len/sway,ascent12/sway,1ace/sway,1ace/sway