[READY] Storing path to Python used in build.py

[Valloric]

We'll use this in YCM to ensure we start ycmd with the same version of
Python that was used for building the C++ libraries loaded into ycmd.

Related to ycm-core/YouCompleteMe#2136

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This change is

[coveralls]

Coverage remained the same at 84.723% when pulling c1cf807 on ubuntu-fix into a3c41b4 on master.

[coveralls]

Coverage remained the same at 84.723% when pulling 0eb4e51 on ubuntu-fix into a3c41b4 on master.

[micbou]

Reviewed 1 of 2 files at r1, 1 of 1 files at r2.
Review status: all files reviewed at latest revision, 1 unresolved discussion.

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build.py, line 43 [r2] (raw file):
This variable is already defined above.

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Comments from Reviewable

[Valloric]

Review status: 1 of 2 files reviewed at latest revision, 1 unresolved discussion.

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build.py, line 43 [r2] (raw file):
Ha, good catch. Fixed.

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Comments from Reviewable

[micbou]

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Reviewed 1 of 1 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[coveralls]

Coverage remained the same at 84.723% when pulling 5390348 on ubuntu-fix into a3c41b4 on master.

[Valloric]

@puremourning @vheon review?

[puremourning]

Only optional thought is maybe prefix the filename with . to make it hidden on UNIX. But meh not a biggie.

fire when ready.

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Reviewed 1 of 2 files at r1, 1 of 1 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[vheon]

@puremourning @vheon review?

I actually tried to do this today from another computer but had a problem with reviewable (and still have) :(

@homu r=micbou

[homu]

📌 Commit 5390348 has been approved by micbou

[homu]

📌 Commit 5390348 has been approved by micbou

[homu]

💡 This pull request was already approved, no need to approve it again.

[homu]

⚡ Test exempted - status