[M3Aggregator ] Fix server address handling if m3msg config stanza present

[yyin-sc]

What this PR does / why we need it:

Fixes #

Don't have an open issue right now, I can go back creating an issue if needed, just want to quickly show my proposed changes for the issue.

The issues was that m3aggregator failed to comes up due to below errors when we trying to update the aggregator server from rawTcp to m3msg.

{"level":"fatal","ts":1597258192.1929145,"msg":"error creating aggregator options","error":"error parsing server address : missing port in address"}

Special notes for your reviewer:

Does this PR introduce a user-facing and/or backwards incompatible change?:

NONE

Does this PR require updating code package or user-facing documentation?:

NONE

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All committers have signed the CLA.

[codecov[bot]]

Codecov Report

Merging #2568 (6c486d3) into master (bf81bda) will increase coverage by 0.0%. Report is 1237 commits behind head on master. The diff coverage is 0.0%.

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #2568   +/-   ##
======================================
  Coverage    71.7%   71.7%           
======================================
  Files        1081    1081           
  Lines       95720   95723    +3     
======================================
+ Hits        68678   68688   +10     
+ Misses      22423   22420    -3     
+ Partials     4619    4615    -4     

Flag	Coverage Δ
aggregator	76.0% <0.0%> (+<0.1%)	:arrow_up:
cluster	85.0% <ø> (ø)
collector	82.8% <ø> (ø)
dbnode	79.3% <ø> (-0.1%)	:arrow_down:
m3em	74.4% <ø> (ø)
m3ninx	72.2% <ø> (ø)
m3nsch	51.1% <ø> (ø)
metrics	17.2% <ø> (ø)
msg	75.1% <ø> (+<0.1%)	:arrow_up:
query	68.0% <ø> (ø)
x	80.9% <ø> (+0.1%)	:arrow_up:

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