Has the verb "to convene" ever been commonly used to mean "to be convenient to"?

Yes. OED has a number of entries showing obsolete usage. It may be that these are too localised to be "commonly used", or perhaps "some parts of New England" is sufficiently common to qualify:

†8. U.S. dialect. To be convenient to; to suit, fit.

1816 J. Pɪᴄᴋᴇʀɪɴɢ Vocab. U.S. Convene..is used in some parts of New England in a very strange sense..‘This road will convene the public,’ i.e. will be convenient for the public. The word, however, is used only by the illiterate.

There are other usages grouped with that under "II. To agree, harmonize":

†5. intransitive. Of persons: To come to agreement in purpose, opinion, or action; to agree. Obsolete.
†6. To agree or accord in size, quality, or character; to be suitable or fitting. convening to: conformable to, according to. Scottish. Obsolete.
†7. transitive. To bring into agreement; to harmonize, settle. Obsolete.

It also has a ninth which is not marked obsolete, although the citation was only forty years old when the definition was included and it may well be obsolete now:

9. intransitive. To come together in harmony; to harmonize, fit each other.

1854 W. M. Tʜᴀᴄᴋᴇʀᴀʏ Newcomes I. xxxi. 305 There are articles which the marriage-monger cannot make to convene at all: tempers..tastes..etc.