Fix format

[michaelortmann]

Found by: michaelortmann
Patch by: michaelortmann
Fixes:

One-line summary:
Fix format for #1390

Additional description (if needed):
snprintf() -> strlcpy()

Test cases demonstrating functionality (if applicable):
Before:

clang -Wno-deprecated-non-prototype -g -O2 -pipe -Wall -I.. -I..  -DHAVE_CONFIG_H -I/usr/include -g3 -DDEBUG -DDEBUG_ASSERT -DDEBUG_MEM -DDEBUG_DNS  -c tclhash.c
tclhash.c:741:57: warning: format string is not a string literal (potentially insecure) [-Wformat-security]
    snprintf(last_bind_called, sizeof last_bind_called, proc);
                                                        ^~~~
tclhash.c:741:57: note: treat the string as an argument to avoid this
    snprintf(last_bind_called, sizeof last_bind_called, proc);
                                                        ^
                                                        "%s", 
1 warning generated.

After:
clang -Wno-deprecated-non-prototype -g -O2 -pipe -Wall -I.. -I.. -DHAVE_CONFIG_H -I/usr/include -g3 -DDEBUG -DDEBUG_ASSERT -DDEBUG_MEM -DDEBUG_DNS -c tclhash.c
New test:
to test this PR, eggdrop has to crash, so i inserted
*(char *) 0xc0ffee = 1;
into cmd_die() to make it crash on .die:

.die
[22:34:36.%f] tcl: builtin dcc call: *dcc:die -HQ 1 
[22:34:36.%f] * Please report problem to https://github.com/eggheads/eggdrop/issues
[22:34:36.%f] * Check doc/BUG-REPORT on how to do so.
[22:34:36.%f] * Last bind (may not be related): evnt:init_server
[22:34:35.%f] * Wrote DEBUG
[22:34:35.%f] * SEGMENT VIOLATION -- CRASHING!
Segmentation fault (core dumped)