Increase size of range request in getrange

32 bit builds don't have a big enough long to capture
the same range as a 64 bit build.  If we use "long long"
we get proper size limits everywhere.

Also updates size of unsigned comparison to fit new size of `end`.

Fixes #1981

src/t_string.c

@@ -231,13 +231,13 @@ void setrangeCommand(redisClient *c) {
 
 void getrangeCommand(redisClient *c) {
     robj *o;
-    long start, end;
+    long long start, end;
     char *str, llbuf[32];
     size_t strlen;
 
-    if (getLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK)
+    if (getLongLongFromObjectOrReply(c,c->argv[2],&start,NULL) != REDIS_OK)
         return;
-    if (getLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK)
+    if (getLongLongFromObjectOrReply(c,c->argv[3],&end,NULL) != REDIS_OK)
         return;
     if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptybulk)) == NULL ||
         checkType(c,o,REDIS_STRING)) return;
@@ -255,7 +255,7 @@ void getrangeCommand(redisClient *c) {
     if (end < 0) end = strlen+end;
     if (start < 0) start = 0;
     if (end < 0) end = 0;
-    if ((size_t)end >= strlen) end = strlen-1;
+    if ((unsigned long long)end >= strlen) end = strlen-1;
 
     /* Precondition: end >= 0 && end < strlen, so the only condition where
      * nothing can be returned is: start > end. */