possible crash send sending notifications

[ntadas]

Hi,

In session.c line 1572 https://github.com/CESNET/libnetconf/blob/master/src/session.c#L1572
the strlen (text) should be checked before accessing the content of the text.
currently I'm having a crash (very sporadic) and I was able to nail it until here (not sure the content of "text" when the crash happens).

#2 0x0f230968 in crashHandler (signo=<optimized out>, sigInfo=<optimized out>, ptr=<optimized out>) at ../base/src/crashHandler.c:62 #3 <signal handler called> #4 0x4821bfac in write () from /lib/libpthread.so.0 #5 0x0fb7b850 in nc_session_send (session=0x26d59ef0, msg=0x2a29a0c0) at src/session.c:1572 #6 0x0fb7ea78 in nc_session_send_reply (session=0x26d59ef0, rpc=0x2a29a330, reply=0x268f7ef0) at src/session.c:2945