Terminal: Fix mismatching malloc/delete

fAlternateScreen is allocated by malloc() in
BasicTerminalBuffer::_AllocateLines(), but freed by delete.
Pointed out by LGTM.

Change-Id: I526ecd7e570caf7d5ed90c715bbbfaf40e7e4be6
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1882
Reviewed-by: Axel Dörfler <[email protected]>

src/apps/terminal/TerminalBuffer.cpp

@@ -39,7 +39,7 @@ TerminalBuffer::TerminalBuffer()
 
 TerminalBuffer::~TerminalBuffer()
 {
-	delete fAlternateScreen;
+	free(fAlternateScreen);
 	delete fAlternateHistory;
 	delete[] fColorsPalette;
 }