Amend 44816adce6: Be careful before using buffer parameters in colAlign

The LASSERT(isBufferValid()..) leads to crash in find-adv dialog

src/mathed/InsetMathGrid.cpp

@@ -1821,9 +1821,17 @@ char InsetMathGrid::colAlign(HullType type, col_type col) const
 	case hullMultline:
 		return 'c';
 	case hullGather:
+		#if 0
+		// Partly revert 44816adce63
+		// because the following test leads to crash
+		// Open a new lyx-file
+		// select findadv dialog
+		// in the search-field enter math
+		// use math-mutate gather ===> crash (because isValidBuffer() == false)
 		LASSERT(isBufferValid(),
 				LYXERR0("Buffer not set correctly. Please report!");
 				return 'c';);
+		#endif
 		if (buffer().params().is_math_indent)
 			return 'l';
 		else