fix heuristics.c from crashing

[elfmaster]

When using -h option certain processes crash because of bug in heuristics.c in checking for dlopen'd libs.

Output from /var/log/syslog

Mar 5 13:06:15 elfmaster ecfs: no calls to dlopen found in /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2.2 [line: 409]
Mar 5 13:06:15 elfmaster ecfs: no calls to dlopen found in /usr/lib/x86_64-linux-gnu/libk5crypto.so.3.1 [line: 409]
Mar 5 13:06:15 elfmaster ecfs: no calls to dlopen found in /usr/lib/x86_64-linux-gnu/libkrb5.so.3.3 [line: 409]
Mar 5 13:06:15 elfmaster kernel: [32130.875632] ecfs[26549]: segfault at f ip 00007f70538a6a03 sp 00007fff4f9c43e0 error 4 in libc-2.19.so[7f705385b000
+1bb000]