Adds expected_errors decorator for API v3

Adds an expected_errors decorator for v3 API methods which allows
the specification of what exceptions can be raised within the
method. If an unexpected error occurs a 500 is instead returned
which plus a request to file a bug report

Partially implements blueprint v3-api-expected-errors

Change-Id: I5723e576b30b47744394517cdb1ff6bab1d8f78b
Add invalid number checking in flavor creation api

Flavor creation api doesn't check whether 'memory_mb'
argument number is integer,add invalid number checking
into the flavor creation function to remind the user to
input right value

Fixes bug #1171278

Change-Id: I8308f66c485d8c872864661148e9eac7b685e406
Merge "Add invalid number checking in flavor creation api"
Merge "Adds expected_errors decorator for API v3"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp