Fix typo in Snort reload config code for SMTP preprocessor.

# Change Log  #
## Date:  09-25-2013 ##

1.  Patch to correct typo in Snort 2.9.4.6 source code for the SMTP preprocessor in the SMTPReloadVerify() function in the spp_smtp.c file.  The call to sfPolicyUserDataIterate() on line 603 is made pointing to the wrong SMTPConfig structure.  This leads to errors when comparing certain values because the structure being used in the comparison has some values un-initialized.  These errors result in the SMTP preprocessor reload test returning an error when it should not.  The error returned is:

"SMTP reload: Changing the file_depth requires a restart."

The returned error causes a Snort soft reload of a new configuration to fail.  This bug is fixed in later versions (2.9.5 and up) of the Snort binary.  This patch back fits the fix to the 2.9.4.6 binary currently used with the Snort package.