Fix memory leak in filesys.mod

[michaelortmann]

Found by: michaelortmann
Patch by: michaelortmann
Fixes:

One-line summary:
Fix memory leak in filesys.mod

Additional description (if needed):

Test cases demonstrating functionality (if applicable):

CFLAGS="-O0 -g3 -fsanitize=address,undefined" ./configure
...
.files
[22:01:32] tcl: builtin dcc call: *dcc:files -HQ 1 
[22:01:32] #-HQ# files
Entering file system...
*** -HQ has left: file system

Welcome to the BotA file server
All file transfers will be sent to '-HQ' by default.
(You can specify an alternate nick with the 'get' command.)
Type 'help' for help.
Current directory: /

cd incoming/../incoming/
New current directory: /incoming
.quit
*** Ja mata!
Returning you to command mode...
*** -HQ has returned.
.die 
[22:01:39] tcl: builtin dcc call: *dcc:die -HQ 1 
[22:01:39] #-HQ# die 
*** BOT SHUTDOWN (Authorized by -HQ)
[22:01:39] Writing user file...
[22:01:39] Writing channel file...
[22:01:39] * DIE BY -HQ!llama@console (request)

=================================================================
==350636==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 9 byte(s) in 1 object(s) allocated from:
    #0 0x7f5a90920cb5 in malloc /usr/src/debug/gcc/gcc/libsanitizer/asan/asan_malloc_linux.cpp:67
    #1 0x55aa428bfaea in n_malloc /home/michael/projects/eggdrop/src/mem.c:341
    #2 0x55aa428d5482 in mod_malloc /home/michael/projects/eggdrop/src/modules.c:1015
    #3 0x7b5a8aeccc19 in resolve_dir .././filesys.mod/files.c:244
    #4 0x7b5a8aecfa1d in cmd_chdir .././filesys.mod/files.c:342
    #5 0x7b5a8af3b2a4 in builtin_fil .././filesys.mod/filesys.c:501
    #6 0x55aa428f808c in tcl_call_stringproc_cd /home/michael/projects/eggdrop/src/tcl.c:340
    #7 0x7f5a9067b7e8 in TclNRRunCallbacks /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:4541
    #8 0x7f5a9067d973 in TclEvalEx /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:5409
    #9 0x7f5a9067e31a in Tcl_EvalEx /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:5075
    #10 0x7f5a9067e33a in Tcl_Eval /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:6001
    #11 0x7f5a9067e98f in Tcl_VarEvalVA /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:7001
    #12 0x7f5a9067ea71 in Tcl_VarEval /usr/src/debug/tcl/tcl8.6.16/generic/tclBasic.c:7033
    #13 0x55aa42922a01 in trigger_bind /home/michael/projects/eggdrop/src/tclhash.c:745
    #14 0x55aa42923fea in check_tcl_bind /home/michael/projects/eggdrop/src/tclhash.c:941
    #15 0x7b5a8af2d40d in check_tcl_fil .././filesys.mod/filesys.c:146
    #16 0x7b5a8af2fb1e in got_files_cmd .././filesys.mod/filesys.c:220
    #17 0x7b5a8af3140b in dcc_files .././filesys.mod/filesys.c:245
    #18 0x55aa428bb49d in mainloop main.c:788
    #19 0x55aa428bfa05 in main main.c:1220
    #20 0x7f5a8f227634  (/usr/lib/libc.so.6+0x27634) (BuildId: b5723831519024d9389a7453760c470fe9bb8dd1)
    #21 0x7f5a8f2276e8 in __libc_start_main (/usr/lib/libc.so.6+0x276e8) (BuildId: b5723831519024d9389a7453760c470fe9bb8dd1)
    #22 0x55aa427d2524 in _start (/home/michael/eggdrop/eggdrop-1.10.1+0x275524) (BuildId: 5037b95baac81f36ecc58c5cef78ba78dfcf0b77)

SUMMARY: AddressSanitizer: 9 byte(s) leaked in 1 allocation(s).