rename the dbname configuration option to tablename.

Sorry for this - I noticed that I named this option quite unfortunately
while writing the documentation.

The patch also removes the dbname configuration option from the sqlite
input reader - it was not used there at all anymore (and I did not notice
that).

testing/btest/scripts/base/frameworks/input/sqlite/basic.bro

@@ -89,7 +89,6 @@ event bro_init()
 	{
 	local config_strings: table[string] of string = {
 		 ["query"] = "select * from conn;",
-		 ["dbname"] = "conn"
 	};
 
 	outfile = open("../out");

testing/btest/scripts/base/frameworks/input/sqlite/error.bro

@@ -83,12 +83,10 @@ event bro_init()
 	{
 	local config_strings: table[string] of string = {
 		 ["query"] = "select * from ssh;",
-		 ["dbname"] = "ssh"
 	};
 	
 	local config_strings2: table[string] of string = {
 		 ["query"] = "select b, g, h from ssh;",
-		 ["dbname"] = "ssh"
 	};
 
 	outfile = open("../out");

testing/btest/scripts/base/frameworks/input/sqlite/port.bro

@@ -39,7 +39,6 @@ event bro_init()
 	{
 	local config_strings: table[string] of string = {
 		 ["query"] = "select port as p, proto from port;",
-		 ["dbname"] = "port"
 	};
 
 	outfile = open("../out");

testing/btest/scripts/base/frameworks/input/sqlite/types.bro

@@ -77,7 +77,6 @@ event bro_init()
 	{
 	local config_strings: table[string] of string = {
 		 ["query"] = "select * from ssh;",
-		 ["dbname"] = "ssh"
 	};
 
 	outfile = open("../out");