Don't leak the memory we've just malloced if we can't find the

process we're looking for. (I don't think this can currently
happen, but it depends how the function is called).

PR:		25932
Submitted by:	David Xu <davidx@viasoft.com.cn>

sys/kern/kern_proc.c

@@ -187,10 +187,10 @@ enterpgrp(p, pgid, mksess)
 		 */
 		KASSERT(p->p_pid == pgid,
 		    ("enterpgrp: new pgrp and pid != pgid"));
-		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
-		    M_WAITOK);
 		if ((np = pfind(savepid)) == NULL || np != p)
 			return (ESRCH);
+		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
+		    M_WAITOK);
 		if (mksess) {
 			register struct session *sess;