Fix ability to overwrite overquota'ed cloud storage

This commit fixes deleting all entries when cloud
storage usage is beyond allowed limit.

The issue would prevent pushing new data well within
quota limit because the old data beyond limit was
never removed in the first place.

platform/chromium/vapi-background.js

@@ -1522,8 +1522,6 @@ vAPI.cloud = (( ) => {
         maxChunkSize = evalMaxChunkSize();
     }, { once: true });
 
-    const maxStorageSize = QUOTA_BYTES;
-
     const options = {
         defaultDeviceName: window.navigator.platform,
         deviceName: undefined,
@@ -1562,13 +1560,7 @@ vAPI.cloud = (( ) => {
     const deleteChunks = async function(datakey, start) {
         const keys = [];
 
-        // No point in deleting more than:
-        // - The max number of chunks per item
-        // - The max number of chunks per storage limit
-        const n = Math.min(
-            maxChunkCountPerItem,
-            Math.ceil(maxStorageSize / maxChunkSize)
-        );
+        const n = await getCoarseChunkCount(datakey);
         for ( let i = start; i < n; i++ ) {
             keys.push(datakey + i.toString());
         }
@@ -1612,7 +1604,7 @@ vAPI.cloud = (( ) => {
         // this will free storage space which could otherwise cause the push
         // operation to fail.
         try {
-            await deleteChunks(datakey, chunkCount);
+            await deleteChunks(datakey, chunkCount + 1);
         } catch (reason) {
         }