Fix travis (does not support c11)

Jan Breuer

2016-05-31 9760a97b3e0260c71d535bc8712b53a8876ff5e7

 libscpi/inc/scpi/types.h

@@ -203,7 +203,7 @@

    struct _scpi_error_info_heap_t {
        size_t wr;
        //size_t rd;
        /* size_t rd; */
        size_t count;
        size_t size;
        char * data;