Hush some harmless compiler warnings in the URI parsing logic.

FossilOrigin-Name: 0206bc6f87bb9393218a380fc5b18039d334a8d8
diff --git a/src/main.c b/src/main.c
index c99d396..d3386eb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1938,9 +1938,9 @@
           const char *z;
           int mode;
         } *aMode = 0;
-        char *zModeType;
-        int mask;
-        int limit;
+        char *zModeType = 0;
+        int mask = 0;
+        int limit = 0;
 
         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
           static struct OpenMode aCacheMode[] = {