Updated the OpenSSL dependency (#577)

Summary:
This PR updates the openssl dependency with OpenSSL-Universal, which ships a fat-binary of libssl and libcrypto with all the architecture.

This PR also updates the travis to cache cocoapods checkout directory.

## Changelog

Updated Flipper-Folly deps
Pull Request resolved: https://github.com/facebook/flipper/pull/577

Test Plan: CI

Reviewed By: jknoxville

Differential Revision: D17877304

Pulled By: priteshrnandgaonkar

fbshipit-source-id: 9d13308108b6665d4bf5dd6145fcaafa2a2a8a13

iOS/Podspecs/Flipper-Folly.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |spec|
   spec.name = 'Flipper-Folly'
-  spec.version = '2.0.0'
+  spec.version = '2.0.2'
   spec.license = { :type => 'Apache License, Version 2.0' }
   spec.homepage = 'https://github.com/facebook/folly'
   spec.summary = 'An open-source C++ library developed and used at Facebook.'
@@ -11,7 +11,7 @@ Pod::Spec.new do |spec|
   spec.dependency 'boost-for-react-native'
   spec.dependency 'DoubleConversion'
   spec.dependency 'glog'
-  spec.dependency 'openssl-ios-bitcode', '~> 1.0'
+  spec.dependency 'OpenSSL-Universal', '1.0.2.19'
   spec.dependency 'CocoaLibEvent', '~> 1.0'
   spec.compiler_flags = '-DFOLLY_HAVE_PTHREAD=1 -DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_HAVE_LIBGFLAGS=0 -DFOLLY_HAVE_LIBJEMALLOC=0 -DFOLLY_HAVE_PREADV=0 -DFOLLY_HAVE_PWRITEV=0 -DFOLLY_HAVE_TFO=0 -DFOLLY_USE_SYMBOLIZER=0
     -frtti