Fix error parsing in build_tools/error_filter.py (#4247)

Summary:
The error_filter.py script parses the output of the "Build and run" stage of continuous tests to check for errors. It is currently only detecting compile errors and not link errors. This change fixes that.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4247

Differential Revision: D9233735

Pulled By: anand1976

fbshipit-source-id: 16e5a04950891cd9aba5cb3efcb6abc2a2e0d5ae

build_tools/error_filter.py

@@ -64,8 +64,12 @@ class MatchErrorParser(ErrorParserBase):
 
 class CompilerErrorParser(MatchErrorParser):
     def __init__(self):
-        # format: '<filename>:<line #>:<column #>: error: <error msg>'
+        # format (compile error):
-        super(CompilerErrorParser, self).__init__(r'\S+:\d+:\d+: error:')
+        #   '<filename>:<line #>:<column #>: error: <error msg>'
+        # format (link error):
+        #   '<filename>:<line #>: error: <error msg>'
+        # The below regex catches both
+        super(CompilerErrorParser, self).__init__(r'\S+:\d+: error:')
 
 
 class ScanBuildErrorParser(MatchErrorParser):