Add full support for Boto

Before this change, vcrpy would not work with modules of Boto (e.g., boto.iam)
that use Boto's CertValidatingHTTPSConnection to connect to AWS (unless you
went through the extra effort of disabling certificate validation during the
tests).  This change adds support for those modules.

vcr/patch.py

@@ -33,6 +33,13 @@ try:
 except ImportError:  # pragma: no cover
     pass
 
+try:
+    # Try to save the original types for boto
+    import boto.https_connection
+    _CertValidatingHTTPSConnection = boto.https_connection.CertValidatingHTTPSConnection
+except ImportError:  # pragma: no cover
+    pass
+
 
 def install(cassette):
     """
@@ -86,6 +93,15 @@ def install(cassette):
     except ImportError:  # pragma: no cover
         pass
 
+    # patch boto
+    try:
+        import boto.https_connection as cpool
+        from .stubs.boto_stubs import VCRCertValidatingHTTPSConnection
+        cpool.CertValidatingHTTPSConnection = VCRCertValidatingHTTPSConnection
+        cpool.CertValidatingHTTPSConnection.cassette = cassette
+    except ImportError:  # pragma: no cover
+        pass
+
 
 def reset():
     '''Undo all the patching'''
@@ -120,3 +136,9 @@ def reset():
         cpool.SCHEME_TO_CONNECTION = _SCHEME_TO_CONNECTION
     except ImportError:  # pragma: no cover
         pass
+
+    try:
+        import boto.https_connection as cpool
+        cpool.CertValidatingHTTPSConnection = _CertValidatingHTTPSConnection
+    except ImportError:  # pragma: no cover
+        pass