Catch web3 initialization errors properly

[sliptype]

Summary

The WEB3_FAILED action is never being dispatched. This is because when injected web3 is missing, the error is caught in initializeDrizzle instead of callInitializeWeb3. This is causing web3.status in the redux state to be 'initialized'.

Steps to reproduce

Initialize drizzle without metamask enabled.

Changes included in PR

• callInitializeWeb3 is removed in favor of wrapping the contents of initializeWeb3 in a try...catch
• store.dispatch({type: 'WEB3_FAILED', error}) is replaced with yield put({type: 'WEB3_FAILED', error})
• The existence of web3 is asserted in initializeDrizzle

[OnlyOneJMJQ]

Thank you @sklingler93 , good catch!