Fixed spelling of 'existent' in various testsuite scripts.

tests/exists.svtest

@@ -17,7 +17,7 @@ test "EXISTS-one" {
 	}
 
 	if exists "x-nonsense" {
-        test_fail "exists test found non-existant header";
+        test_fail "exists test found non-existent header";
     }
 }
 
@@ -27,7 +27,7 @@ test "EXISTS-two" {
     }
 
     if exists ["from","to","x-nonsense"] {
-        test_fail "exists test found non-existant header";
+        test_fail "exists test found non-existent header";
     }
 }
 
@@ -37,6 +37,6 @@ test "EXISTS-three" {
     }
 
     if exists ["x-spam", "sub", "resent"] {
-        test_fail "exists test found non-existant header";
+        test_fail "exists test found non-existent header";
     }
 }

tests/extensions/body/basic.svtest

@@ -84,14 +84,14 @@ Subject: No body is here!
 
 test "No body" {
 	if body :raw :contains "" {
-		test_fail "matched against non-existant body (:contains \"\")";
+		test_fail "matched against non-existent body (:contains \"\")";
 	}
 
 	if body :raw :is "" {
-		test_fail "matched against non-existant body (:is \"\")";
+		test_fail "matched against non-existent body (:is \"\")";
 	}
 
 	if body :raw :matches "*" {
-		test_fail "matched against non-existant body (:matches \"*\")";
+		test_fail "matched against non-existent body (:matches \"*\")";
 	}
 }

tests/extensions/environment/rfc.svtest

@@ -2,7 +2,7 @@ require "vnd.dovecot.testsuite";
 require "environment";
 require "relational";
 
-test "Non-existant" {
+test "Non-existent" {
 	if environment :contains "nonsense" "" {
 		test_fail "matched unknown environment item";	
 	}

tests/extensions/include/errors/generic.sieve

 require "include";
 
-# Non-existant sieve script
+# Non-existent sieve script
 include "frop.sieve";
 
 # Use of / in script names

tests/extensions/subaddress/basic.svtest

@@ -102,10 +102,10 @@ test_set "envelope.to" "frop@sieve.nl";
 
 test "No detail" {
 	if envelope :detail "to" "virus" {
-		test_fail ":detail matched non-existant detail element in envelope (separator is missing)";
+		test_fail ":detail matched non-existent detail element in envelope (separator is missing)";
 	}
 
 	if address :detail "from" "virus" {
-		test_fail ":detail matched non-existant detail element in from header (separator is missing)";		
+		test_fail ":detail matched non-existent detail element in from header (separator is missing)";		
 	}
 }

tests/header.svtest

@@ -45,7 +45,7 @@ test "Contains empty - exist" {
 
 test "Contains empty - not exist" {
 	if header :contains "x-nonsense" "" {
-		test_fail "header test :contains match type matches \"\" on non-existant header";
+		test_fail "header test :contains match type matches \"\" on non-existent header";
 	}
 }