some weird error caused crash of sis-api

[DrMegavolt]

sls:main TypeError: Cannot read property 'on' of undefined
at Git._schedule (/usr/src/app/node_modules/simple-git/src/git.js:1341:25)
at Git._run (/usr/src/app/node_modules/simple-git/src/git.js:1317:12)
at Git.revparse (/usr/src/app/node_modules/simple-git/src/git.js:1073:19)
at latestRev (/usr/src/app/lib/git.js:24:15)
at ServerlessExecutor.listServices (/usr/src/app/lib/serverless-executor.js:135:28)
events.js:167
throw er; // Unhandled 'error' event
^

Error: spawn git EAGAIN
at Process.ChildProcess._handle.onexit (internal/child_process.js:232:19)
at onErrorNT (internal/child_process.js:407:16)
at process._tickCallback (internal/process/next_tick.js:63:19)
Emitted 'error' event at:
at Process.ChildProcess._handle.onexit (internal/child_process.js:238:12)
at onErrorNT (internal/child_process.js:407:16)
at process._tickCallback (internal/process/next_tick.js:63:19)