Teach coverity that pipe initializes its argument

Call pipe2 for a return value, so that coverity cannot infer a
fixed return value.

Author: eldering

coverity/modeling.c

@@ -6,3 +6,9 @@
 void error(int errnum, const char *format, ...) {
 	__coverity_panic__();
 }
+
+int pipe(int pipefd[2]) {
+	pipefd[0] = 1;
+	pipefd[2] = 2;
+	return pipe2(pipefd, 0);
+}