[INSTALL] delete net-snmp-5.7.2.1 build-dir prior to rebuilding it
[INSTALL] delete net-snmp-5.7.2.1 build-dir prior to rebuilding it

Signed-off-by: Robert Wuttke <12e9293ec6b30c7fa8a0926af42807e929c1684f@benocs.com>

Benocs/core,Benocs/core,Benocs/core,Benocs/core,Benocs/core