test: POSIX, stop FD_Fail to fail

In our build environments, /etc/fstab is an empty file. Use /etc/mtab,
which should be non-empty anywhere, hopefully.

For the reference, the test fails as follows:
FAIL: KLEE :: Runtime/POSIX/FD_Fail.c (188 of 212)
************ TEST 'KLEE :: Runtime/POSIX/FD_Fail.c' FAILED ************
Script:
--
clang-3.8 -Iinclude test/Runtime/POSIX/FD_Fail.c -emit-llvm -O0 -c -o build/test/Runtime/POSIX/Output/FD_Fail.c.tmp1.bc
rm -rf build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.klee-out
build/bin/klee --output-dir=build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.klee-out --libc=uclibc --posix-runtime build/test/Runtime/POSIX/Output/FD_Fail.c.tmp1.bc --sym-files 0 0 --max-fail 1 > build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.log
grep -q "fread(): ok" build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.log
grep -q "fread(): fail" build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.log
grep -q "fclose(): ok" build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.log
grep -q "fclose(): fail" build/test/Runtime/POSIX/Output/FD_Fail.c.tmp.log
--
Exit Code: 1

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/test/Runtime/POSIX/FD_Fail.c b/test/Runtime/POSIX/FD_Fail.c
index 186ada51..2ee1a1a2 100644
--- a/test/Runtime/POSIX/FD_Fail.c
+++ b/test/Runtime/POSIX/FD_Fail.c
@@ -11,7 +11,7 @@
 
 int main(int argc, char** argv) {
   char buf[1024];  
-  FILE* f = fopen("/etc/fstab", "r");
+  FILE* f = fopen("/etc/mtab", "r");
   assert(f);
     
   int r = fread(buf, 1, 100, f);