utils: Change sh(1) "test ==" usage to "="

The POSIX sh(1) specification says that strings are compared with
test(1) (also "[") with "=".  Bash accepts "==" and this leads to
non-portable code.  This commit simply changes "==" within test/[ to
"=".

utils/kamctl/kamdbctl

@@ -153,7 +153,7 @@ kamailio_dump()  # pars: <database name>
 		merr "kamailio_dump function takes two param"
 		exit 1
 	fi
-	if [ "$USED_DBENGINE" == "oracle" ]; then
+	if [ "$USED_DBENGINE" = "oracle" ]; then
 		oracle_dump $1 $2
 	elif [ "$PW" = "" ] ; then
 		$DUMP_CMD $1 > $2
@@ -174,7 +174,7 @@ kamailio_restore() #pars: <database name> <filename>
 		merr "kamailio_restore function takes two params"
 		exit 1
 	fi
-	if [ "$USED_DBENGINE" == "oracle" ]; then
+	if [ "$USED_DBENGINE" = "oracle" ]; then
 		oracle_restore $1 $2
 	else
 		sql_query $1 < $2
@@ -290,7 +290,7 @@ kamailio_pframework() #pars: <action>
 case $1 in
 	copy)
 		# copy database to some other name
-		if [ "$USED_DBENGINE" == "berkeley" -o "$USED_DBENGINE" == "dbtext" ] ; then
+		if [ "$USED_DBENGINE" = "berkeley" -o "$USED_DBENGINE" = "dbtext" ] ; then
 			merr "$USED_DBENGINE don't support this operation"
 			exit 1
 		fi
@@ -323,7 +323,7 @@ case $1 in
 		exit $ret
 		;;
 	backup)
-		if [ "$USED_DBENGINE" == "berkeley" -o "$USED_DBENGINE" == "dbtext" ] ; then
+		if [ "$USED_DBENGINE" = "berkeley" -o "$USED_DBENGINE" = "dbtext" ] ; then
 			merr "$USED_DBENGINE don't support this operation"
 			exit 1
 		fi
@@ -337,7 +337,7 @@ case $1 in
 		exit $?
 		;;
 	restore)
-		if [ "$USED_DBENGINE" == "berkeley" -o "$USED_DBENGINE" == "dbtext" ] ; then
+		if [ "$USED_DBENGINE" = "berkeley" -o "$USED_DBENGINE" = "dbtext" ] ; then
 			merr "$USED_DBENGINE don't support this operation"
 			exit 1
 		fi