Free log_impl on error to avoid memory leak

JIRA: AXIS2C-1655


diff --git a/util/src/log.c b/util/src/log.c
index 6cd7f0f..7172f52 100644
--- a/util/src/log.c
+++ b/util/src/log.c
@@ -120,6 +120,7 @@
     if(!log_impl->mutex)
     {
         fprintf(stderr, "cannot create log mutex \n");
+        AXIS2_FREE(allocator, log_impl);
         return NULL;
     }