drizzled crashes on startup if dead dfe file exists in /tmp/

[Brian Aker]

Create a file like this:
touch /tmp/#sqlrandom.dfe

Then drizzled will core with the following:
Program received signal SIGSEGV, Segmentation fault.
strlen () at ../sysdeps/x86_64/strlen.S:31
31 movdqa (%rdi), %xmm0
Current language: auto; currently asm
(gdb) backtrace
#0 strlen () at ../sysdeps/x86_64/strlen.S:31
#1 0x00000000004f525d in TableShare::init (new_path=<value optimized out>, new_table_name=<value optimized out>,
    key_length=<value optimized out>, key=<value optimized out>, this=<value optimized out>) at ../drizzled/table_share.h:282
#2 TableShare::init (new_path=<value optimized out>, new_table_name=<value optimized out>, key_length=<value optimized out>,
    key=<value optimized out>, this=<value optimized out>) at ../drizzled/table_share.h:266
#3 drizzle_rm_tmp_tables (new_path=<value optimized out>, new_table_name=<value optimized out>, key_length=<value optimized out>,
    key=<value optimized out>, this=<value optimized out>) at sql_base.cc:4579
#4 0x0000000000410fc2 in main (argc=<value optimized out>, argv=<value optimized out>) at drizzled.cc:1549