HPCC-17050 Coverity: uninitialised fields in metaphone code

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>

plugins/dmetaphone/metaphone.h

@@ -26,8 +26,9 @@ namespace nsDmetaphone {
 
 class DMETAPHONE_API MString : public cString
 {
-        int             length, last;
-        bool    alternate;
+        int     length = 0;
+        int     last = 0;
+        bool    alternate = false;
         cString primary, secondary;
 
 public: